| | |
- arange(...)
- arange(start, stop=None, step=1, typecode=None)
Just like range() except it returns an array whose type can be
specified by the keyword argument typecode.
- array(...)
- array(sequence, typecode=None, copy=1, savespace=0) will return a new array formed from the given (potentially nested) sequence with type given by typecode. If no typecode is given, then the type will be determined as the minimum type required to hold the objects in sequence. If copy is zero and sequence is already an array, a reference will be returned. If savespace is nonzero, the new array will maintain its precision in operations.
- arrayrange = arange(...)
- arange(start, stop=None, step=1, typecode=None)
Just like range() except it returns an array whose type can be
specified by the keyword argument typecode.
- axes(*args, **kwargs)
- Add an axis at positon rect specified by
axes() by itself creates a default full subplot(111) window axis
axes(rect, axisbg='w') where rect=[left, bottom, width, height]
in normalized (0,1) units. axisbg is the background color for
the axis, default white
axes(h) where h is an axes instance makes h the
current axis An Axes instance is returned
axisbg is a color format string which sets the background color of
the axes
If axisbg is a length 1 string, assume it's a color format string
(see plot for legal color strings). If it is a length 7 string,
assume it's a hex color string, as used in html, eg, '#eeefff'.
If it is a len(3) tuple, assume it's an rgb value where r,g,b in
[0,1].
- axhline(y=0, xmin=0, xmax=1, **kwargs)
- axhline : Axis Horizontal Line
Draw a horizontal line at y from xmin to xmax. With the default
values of xmin=0 and xmax=1, this line will always span the horizontal
extent of the axes, regardless of the xlim settings, even if you
change them, eg with the xlim command. That is, the horizontal extent
is in axes coords: 0=left, 0.5=middle, 1.0=right but the y location is
in data coordinates.
return value is the Line2D instance. kwargs are the same as kwargs to
plot, and can be used to control the line properties. Eg
# draw a thick red hline at y=0 that spans the xrange
l = axhline(linewidth=4, color='r')
# draw a default hline at y=1 that spans the xrange
l = axhline(y=1)
# draw a default hline at y=.5 that spans the the middle half of
# the xrange
l = axhline(y=.5, xmin=0.25, xmax=0.75)
ylim(-1,2)
- axhspan(ymin, ymax, xmin=0, xmax=1, **kwargs)
- axhspan : Axis Horizontal Span. ycoords are in data units and x
coords are in axes (relative 0-1) units
Draw a horizontal span (regtangle) from ymin to ymax. With the
default values of xmin=0 and xmax=1, this always span the xrange,
regardless of the xlim settings, even if you change them, eg with the
xlim command. That is, the horizontal extent is in axes coords:
0=left, 0.5=middle, 1.0=right but the y location is in data
coordinates.
kwargs are the kwargs to Patch, eg
antialiased, aa
linewidth, lw
edgecolor, ec
facecolor, fc
the terms on the right are aliases
return value is the patches.Polygon instance.
#draws a gray rectangle from y=0.25-0.75 that spans the horizontal
#extent of the axes
p = axhspan(0.25, 0.75, facecolor=0.5, alpha=0.5)
- axis(*v)
- axis() returns the current axis as a length a length 4 vector
axis(v) where v= [xmin xmax ymin ymax] sets the min and max of the
x and y axis limits
axis('off') turns off the axis lines and labels
axis('equal') sets the xlim width and ylim height to be to be
identical. The longer of the two intervals is chosen
- axvline(x=0, ymin=0, ymax=1, **kwargs)
- axvline : Axis Vertical Line
Draw a vertical line at x from ymin to ymax. With the default values
of ymin=0 and ymax=1, this line will always span the vertical extent
of the axes, regardless of the xlim settings, even if you change them,
eg with the xlim command. That is, the vertical extent is in axes
coords: 0=bottom, 0.5=middle, 1.0=top but the x location is in data
coordinates.
return value is the Line2D instance. kwargs are the same as
kwargs to plot, and can be used to control the line properties. Eg
# draw a thick red vline at x=0 that spans the yrange
l = axvline(linewidth=4, color='r')
# draw a default vline at x=1 that spans the yrange
l = axvline(x=1)
# draw a default vline at x=.5 that spans the the middle half of
# the yrange
l = axvline(x=.5, ymin=0.25, ymax=0.75)
xlim(-1,2)
- axvspan(xmin, xmax, ymin=0, ymax=1, **kwargs)
- axvspan : Axis Vertical Span. xcoords are in data units and y coords
are in axes (relative 0-1) units
Draw a vertical span (regtangle) from xmin to xmax. With the default
values of ymin=0 and ymax=1, this always span the yrange, regardless
of the ylim settings, even if you change them, eg with the ylim
command. That is, the vertical extent is in axes coords: 0=bottom,
0.5=middle, 1.0=top but the y location is in data coordinates.
kwargs are the kwargs to Patch, eg
antialiased, aa
linewidth, lw
edgecolor, ec
facecolor, fc
the terms on the right are aliases
return value is the patches.Polygon instance.
# draw a vertical green translucent rectangle from x=1.25 to 1.55 that
# spans the yrange of the axes
p = axvspan(1.25, 1.55, facecolor='g', alpha=0.5)
- bar(*args, **kwargs)
- BAR(left, height)
Make a bar plot with rectangles at
left, left+width, 0, height
left and height are Numeric arrays
Return value is a list of Rectangle patch instances
BAR(left, height, width, bottom,
color, yerr, xerr, capsize, yoff)
xerr and yerr, if not None, will be used to generate errorbars
on the bar chart
color specifies the color of the bar
ecolor specifies the color of any errorbar
capsize determines the length in points of the error bar caps
The optional arguments color, width and bottom can be either
scalars or len(x) sequences
This enables you to use bar as the basis for stacked bar
charts, or candlestick plots
- choose(...)
- choose(a, (b1,b2,...))
- cla()
- Clear the current axes
- clf()
- Clear the current figure
- clim(vmin=None, vmax=None)
- Set the color limits of the current image
To apply clim to all axes images do
clim(0, 0.5)
If either vmin or vmax is None, the image min/max respectively
will be used for color scaling.
If you want to set the clim of multiple images,
use, for example for im in gca().get_images(): im.set_clim(0,
0.05)
- close(*args)
- Close a figure window
close() by itself closes the current figure
close(num) closes figure number num
close(h) where h is a figure handle(instance) closes that figure
close('all') closes all the figure windows
- cohere(x, y, NFFT=256, Fs=2, detrend=<function detrend_none>, window=<function window_hanning>, noverlap=0)
- Compute the coherence between x and y. Coherence is the
normalized cross spectral density
Cxy = |Pxy|^2/(Pxx*Pyy)
The return value is (Cxy, f), where f are the frequencies of the
coherence vector. See the docs for psd and csd for information
about the function arguments NFFT, detrend, windowm noverlap, as
well as the methods used to compute Pxy, Pxx and Pyy.
Returns the tuple Cxy, freqs
Refs:
Bendat & Piersol -- Random Data: Analysis and Measurement
Procedures, John Wiley & Sons (1986)
- colorbar(tickfmt='%1.1f')
- Create a colorbar for current mappable image (see gci)
tickfmt is a format string to format the colorbar ticks
return value is the colorbar axes instance
- colors()
- This is a do nothing function to provide you with help on how
matplotlib handles colors.
Commands which take color arguments can use several formats to
specify the colors. For the basic builtin colors, you can use a
single letter
b : blue
g : green
r : red
c : cyan
m : magenta
y : yellow
k : black
w : white
For a greater range of colors, you have two options. You can
specify the color using an html hex string, as in
color = '#eeefff'
or you can pass an R,G,B tuple, where each of R,G,B are in the
range [0,1]. The example below creates a subplot with a dark
slate gray background
subplot(111, axisbg=(0.1843, 0.3098, 0.3098))
Here is an example that creates a pale turqoise title
title('Is this the best color?', color='#afeeee')
- cross_correlate(...)
- cross_correlate(a,v, mode=0)
- csd(x, y, NFFT=256, Fs=2, detrend=<function detrend_none>, window=<function window_hanning>, noverlap=0)
- The cross spectral density Pxy by Welches average periodogram
method. The vectors x and y are divided into NFFT length
segments. Each segment is detrended by function detrend and
windowed by function window. noverlap gives the length of the
overlap between segments. The product of the direct FFTs of x and
y are averaged over each segment to compute Pxy, with a scaling to
correct for power loss due to windowing. Fs is the sampling
frequency.
NFFT must be a power of 2
detrend and window are functions, unlike in matlab where they are
vectors. For detrending you can use detrend_none, detrend_mean,
detrend_linear or a custom function. For windowing, you can use
window_none, window_hanning, or a custom function
Returns the tuple Pxy, freqs. Pxy is the cross spectrum (complex
valued), and 10*log10(|Pxy|) is plotted
Refs:
Bendat & Piersol -- Random Data: Analysis and Measurement
Procedures, John Wiley & Sons (1986)
- draw()
- redraw the current figure
- errorbar(*args, **kwargs)
- Plot x versus y with error deltas in yerr and xerr.
Vertical errorbars are plotted if yerr is not None
Horizontal errorbars are plotted if xerr is not None
xerr and yerr may be any of:
a rank-0, Nx1 Numpy array - symmetric errorbars +/- value
an N-element list or tuple - symmetric errorbars +/- value
a rank-1, Nx2 Numpy array - asymmetric errorbars -column1/+column2
Alternatively, x, y, xerr, and yerr can all be scalars, which
plots a single error bar at x, y.
fmt is the plot format symbol for y. if fmt is None, just
plot the errorbars with no line symbols. This can be useful
for creating a bar plot with errorbars
ecolor is a matplotlib color arg which gives the color the
errobar lines; if None, use the marker color.
Return value is a length 2 tuple. The first element is a list of
y symbol lines. The second element is a list of error bar lines.
capsize is the size of the error bar caps in points
- figimage(*args, **kwargs)
- FIGIMAGE(X) # add non-resampled array to figure
FIGIMAGE(X, xo, yo) # with pixel offsets
FIGIMAGE(X, **kwargs) # control interpolation ,scaling, etc
Add a nonresampled figure to the figure from array X. xo and yo are
offsets in pixels
X must be a float array
If X is MxN, assume luminance (grayscale)
If X is MxNx3, assume RGB
If X is MxNx4, assume RGBA
The following kwargs are allowed:
* cmap is a cm colormap instance, eg cm.jet. If None, default to
the rc image.cmap valuex
* norm is a matplotlib.colors.normalize instance; default is
normalization(). This scales luminance -> 0-1
* vmin and vmax are used to scale a luminance image to 0-1. If
either is None, the min and max of the luminance values will be
used. Note if you pass a norm instance, the settings for vmin and
vmax will be ignored.
* alpha = 1.0 : the alpha blending value
* origin is either 'upper' or 'lower', which indicates where the [0,0]
index of the array is in the upper left or lower left corner of
the axes. Defaults to the rc image.origin value
This complements the axes image which will be resampled to fit the
current axes. If you want a resampled image to fill the entire
figure, you can define an Axes with size [0,1,0,1].
A image.FigureImage instance is returned.
- figlegend(handles, labels, loc)
- Place a legend in the figure. Labels are a sequence of
strings, handles is a sequence of line or patch instances, and
loc can be a string or an integer specifying the legend
location
USAGE:
legend( (line1, line2, line3),
('label1', 'label2', 'label3'),
'upper right')
See help(legend) for information about the location codes
A matplotlib.legend.Legend instance is returned
- figtext(*args, **kwargs)
- Add text to figure at location x,y (relative 0-1 coords) See
the help for Axis text for the meaning of the other arguments
- figure(num=1, figsize=None, dpi=None, facecolor=None, edgecolor=None, frameon=True)
- figure(num = 1, figsize=(8, 6), dpi=80, facecolor='w', edgecolor='k')
Create a new figure and return a handle to it
If figure(num) already exists, make it active and return the
handle to it.
figure(1)
figsize - width in height x inches; defaults to rc figure.figsize
dpi - resolution; defaults to rc figure.dpi
facecolor - the background color; defaults to rc figure.facecolor
edgecolor - the border color; defaults to rc figure.edgecolor
rcParams gives the default values from the .matplotlibrc file
- fill(*args, **kwargs)
- plot filled polygons. *args is a variable length argument,
allowing for multiple x,y pairs with an optional color format
string. For example, all of the following are legal, assuming a
is the Axis instance:
fill(x,y) # plot polygon with vertices at x,y
fill(x,y, 'b' ) # plot polygon with vertices at x,y in blue
An arbitrary number of x, y, color groups can be specified, as in
fill(x1, y1, 'g', x2, y2, 'r')
Return value is a list of patches that were added
The following color strings are supported
b : blue
g : green
r : red
c : cyan
m : magenta
y : yellow
k : black
w : white
The kwargs that are can be used to set line properties (any
property that has a set_* method). You can use this to set edge
color, face color, etc.
Example code:
from matplotlib.matlab import *
t = arange(0.0, 1.01, 0.01)
s = sin(2*2*pi*t)
fill(t, s, 'r')
grid(True)
show()
- fromstring(...)
- fromstring(string, typecode='l', count=-1) returns a new 1d array initialized from the raw binary data in string. If count is positive, the new array will have count elements, otherwise it's size is determined by the size of string.
- gca()
- Return the current axis instance. This can be used to control
axis properties either using set or the Axes methods.
Example:
plot(t,s)
set(gca(), 'xlim', [0,10]) # set the x axis limits
or
plot(t,s)
a = gca()
a.set_xlim([0,10]) # does the same
- gcf()
- Return a handle to the current figure
- gci()
- get the current ScalarMappable instance (image or patch
collection), or None if no images or patch collecitons have been
defined. The commands imshow and figimage create images
instances, and the commands pcolor and scatter create patch
collection instances
- get(o, s)
- Return the value of handle property s
h is an instance of a class, eg a Line2D or an Axes or Text.
if s is 'somename', this function returns
o.get_somename()
- get_current_fig_manager()
- get_plot_commands()
- gray()
- set the default colormap to gray and apply to current image if any
- grid(b=None)
- Set the figure grid to be on or off (b is a boolean)
if b is None, toggle the grid state
- hbar(*args, **kwargs)
- HBAR(x, y)
The y values give the heights of the center of the bars. The
x values give the length of the bars.
Return value is a list of Rectangle patch instances
Optional arguments
height - the height (thickness) of the bar
left - the x coordinate of the left side of the bar
color specifies the color of the bar
xerr and yerr, if not None, will be used to generate errorbars
on the bar chart
ecolor specifies the color of any errorbar
capsize determines the length in points of the error bar caps
The optional arguments color, height and left can be either
scalars or len(x) sequences
- hist(x, bins=10, noplot=0, normed=0, bottom=0)
- Compute the histogram of x. bins is either an integer number of
bins or a sequence giving the bins. x are the data to be binned.
if noplot is True, just compute the histogram and return the
number of observations and the bins as an (n, bins) tuple.
If noplot is False, compute the histogram and plot it, returning
n, bins, patches
If normed is true, the first element of the return tuple will be the
counts normalized to form a probability distribtion, ie,
n/(len(x)*dbin)
To control the properties of the returned patches, you can can
call any of the patch methods on those patches; see
matplotlib.patches and matplotlib.artist (the base class for
patches). Eg
n, bins, patches = hist(x, 50, normed=1)
set(patches, 'facecolor', 'g', 'alpha', 0.75)
- hlines(*args, **kwargs)
- lines = hlines(self, y, xmin, xmax, fmt='k-')
plot horizontal lines at each y from xmin to xmax. xmin or
xmax can be scalars or len(x) numpy arrays. If they are
scalars, then the respective values are constant, else the
widths of the lines are determined by xmin and xmax
Returns a list of line instances that were added
- hold(b=None)
- Set the hold state. If hold is None (default), toggle the
hold state. Else set the hold state to boolean value b.
Eg
hold() # toggle hold
hold(True) # hold is on
hold(False) # hold is off
- imread(*args, **kwargs)
- return image file in fname as numerix array
Return value is a MxNx4 array of 0-1 normalized floats
- imshow(*args, **kwargs)
- IMSHOW(X) - plot image in array X to current axes, resampling to scale
to axes size
IMSHOW(X, **kwargs) - Use keyword args to control image scaling,
colormapping etc. See below for details
Display the image in array X to current axes. X must be a
float array
If X is MxN, assume luminance (grayscale)
If X is MxNx3, assume RGB
If X is MxNx4, assume RGBA
A matplotlib.image.AxesImage instance is returned
The following kwargs are allowed:
* cmap is a cm colormap instance, eg cm.jet. If None, default to rc
image.cmap value
* aspect is one of: free or preserve. if None, default to rc
image.aspect value
* interpolation is one of: bicubic bilinear blackman100 blackman256
blackman64 nearest sinc144 sinc256 sinc64 spline16 or spline36.
If None, default to rc image.interpolation
* norm is a matplotlib.colors.normalize instance; default is
normalization(). This scales luminance -> 0-1.
* vmin and vmax are used to scale a luminance image to 0-1. If
either is None, the min and max of the luminance values will be
used. Note if you pass a norm instance, the settings for vmin and
vmax will be ignored.
* alpha = 1.0 : the alpha blending value
* origin is either upper or lower, which indicates where the [0,0]
index of the array is in the upper left or lower left corner of
the axes. If None, default to rc image.origin
* extent is a data xmin, xmax, ymin, ymax for making image plots
registered with data plots. Default is the image dimensions
in pixels
- jet()
- set the default colormap to jet and apply to current image if any
- legend(*args, **kwargs)
- Place a legend on the current axes at location loc. Labels are a
sequence of strings and loc can be a string or an integer
specifying the legend location
USAGE:
Make a legend with existing lines
legend( LABELS )
>>> legend( ('label1', 'label2', 'label3') )
Make a legend for Line2D instances lines1, line2, line3
legend( LINES, LABELS )
>>> legend( (line1, line2, line3), ('label1', 'label2', 'label3') )
Make a legend at LOC
legend( LABELS, LOC ) or
legend( LINES, LABELS, LOC )
>>> legend( ('label1', 'label2', 'label3'), loc='upper left')
>>> legend( (line1, line2, line3),
('label1', 'label2', 'label3'),
loc=2)
The LOC location codes are
The LOC location codes are
'best' : 0, (currently not supported, defaults to upper right)
'upper right' : 1, (default)
'upper left' : 2,
'lower left' : 3,
'lower right' : 4,
'right' : 5,
'center left' : 6,
'center right' : 7,
'lower center' : 8,
'upper center' : 9,
'center' : 10,
If none of these are suitable, loc can be a 2-tuple giving x,y
in axes coords, ie,
loc = 0, 1 is left top
loc = 0.5, 0.5 is center, center
and so on
The legend instance is returned
- load(fname)
- Load ASCII data from fname into an array and return the array.
The data must be regular, same number of values in every row
fname can be a filename or a file handle
matfile data is not currently supported, but see
Nigel Wade's matfile ftp://ion.le.ac.uk/matfile/matfile.tar.gz
Example usage:
x,y = load('test.dat') # data in two columns
X = load('test.dat') # a matrix of data
x = load('test.dat') # a single column of data
- loglog(*args, **kwargs)
- Make a loglog plot with log scaling on the a and y axis. The args
to semilog x are the same as the args to plot. See help plot for
more info
Optional keyword args supported are any of the kwargs
supported by plot or set_xscale or set_yscale. Notable, for
log scaling:
basex: base of the x logarithm
subsx: the location of the minor ticks; None defaults to range(2,basex)
basey: base of the y logarithm
subsy: the location of the minor yticks; None defaults to range(2,basey)
- mpl_connect(s, func)
- Connect event with string s to func. The signature of func is
def func(event)
where event is a MplEvent. The following events are recognized
'button_press_event'
'button_release_event'
'motion_notify_event'
For the three events above, if the mouse is over the axes,
the variable event.inaxes will be set to the axes it is over,
and additionally, the variables event.xdata and event.ydata
will be defined. This is the mouse location in data coords.
See backend_bases.MplEvent.
return value is a connection id that can be used with
mpl_disconnect
- mpl_disconnect(cid)
- Connect s to func. return an id that can be used with disconnect
Method should return None
- pcolor(*args, **kwargs)
- PCOLOR(C) - make a pseudocolor plot of matrix C
PCOLOR(X, Y, C) - a pseudo color plot of C on the matrices X and Y
PCOLOR(C, **kwargs) - Use keywork args to control colormapping and
scaling; see below
Optional keywork args are shown with their defaults below (you must
use kwargs for these):
* cmap = cm.jet : a cm Colormap instance from matplotlib.cm.
defaults to cm.jet
* norm = normalize() : matplotlib.colors.normalize is used to scale
luminance data to 0,1.
* vmin=None and vmax=None : vmin and vmax are used in conjunction
with norm to normalize luminance data. If either are None, the
min and max of the color array C is used. If you pass a norm
instance, vmin and vmax will be None
* shading = 'flat' : or 'faceted'. If 'faceted', a black grid is
drawn around each rectangle; if 'flat', edge colors are same as
face colors
* alpha=1.0 : the alpha blending value
Return value is a matplotlib.collections.PatchCollection
object
Note, the behavior of meshgrid in matlab is a bit counterintuitive for
x and y arrays. For example,
x = arange(7)
y = arange(5)
X, Y = meshgrid(x,y)
Z = rand( len(x), len(y))
pcolor(X, Y, Z)
will fail in matlab and matplotlib. You will probably be
happy with
pcolor(X, Y, transpose(Z))
Likewise, for nonsquare Z,
pcolor(transpose(Z))
will make the x and y axes in the plot agree with the numrows and
numcols of Z
- pcolor_classic(*args, **kwargs)
- pcolor_classic(C) - make a pseudocolor plot of matrix C
pcolor_classic(X, Y, C) - a pseudo color plot of C on the matrices X and Y
Shading:
The optional keyword arg shading ('flat' or 'faceted') will
determine whether the black grid is drawn around each pcolor
square. Defaul 'faceteted'
e.g.,
pcolor_classic(C, shading='flat')
pcolor_classic(X, Y, C, shading='faceted')
returns a list of patch objects.
pcolor(C, cmap=cm.jet) - make a pseudocolor plot of matrix C using
rectangle patches using a colormap jet. Colormaps are avalible in
matplotlib.cm. You must pass this as a kwarg.
pcolor(C, norm=normalize()) - the normalization function used to
scale your color data to 0-1. must be passed as a kwarg.
normalization functions are derived from matplotlib.colors.Norm
pcolor(C, alpha=0.5) - set the alpha of the pseudocolor plot.
Must be used as a kwarg
Note, the behavior of meshgrid in matlab is a bit
counterintuitive for x and y arrays. For example,
x = arange(7)
y = arange(5)
X, Y = meshgrid(x,y)
Z = rand( len(x), len(y))
pcolor(X, Y, Z)
will fail in matlab and matplotlib. You will probably be
happy with
pcolor_classic(X, Y, transpose(Z))
Likewise, for nonsquare Z,
pcolor_classic(transpose(Z))
will make the x and y axes in the plot agree with the numrows
and numcols of Z
- plot(*args, **kwargs)
- Emulate matlab's plot command. *args is a variable length
argument, allowing for multiple x,y pairs with an optional
format string. For example, all of the following are legal,
assuming a is the Axis instance:
a.plot(x,y) # plot Numeric arrays y vs x
a.plot(x,y, 'bo') # plot Numeric arrays y vs x with blue circles
a.plot(y) # plot y using x as index array 0..N-1
a.plot(y, 'r+') # ditto with red plusses
An arbitrary number of x, y, fmt groups can be specified, as in
a.plot(x1, y1, 'g^', x2, y2, 'g-')
Return value is a list of lines that were added
The following line styles are supported:
- : solid line
-- : dashed line
-. : dash-dot line
: : dotted line
. : points
, : pixels
o : circle symbols
^ : triangle up symbols
v : triangle down symbols
< : triangle left symbols
> : triangle right symbols
s : square symbols
+ : plus symbols
x : cross symbols
D : diamond symbols
d : thin diamond symbols
1 : tripod down symbols
2 : tripod up symbols
3 : tripod left symbols
4 : tripod right symbols
h : hexagon symbols
H : rotated hexagon symbols
p : pentagon symbols
| : vertical line symbols
_ : horizontal line symbols
steps : use gnuplot style 'steps' # kwarg only
The following color strings are supported
b : blue
g : green
r : red
c : cyan
m : magenta
y : yellow
k : black
w : white
Line styles and colors are combined in a single format string
The kwargs that are can be used to set line properties (any property
that has a set_* method). You can use this to set a line label (for
auto legends), linewidth, anitialising, marker face color, etc. Here
is an example:
plot([1,2,3], [1,2,3], 'go-', label='line 1', linewidth=2)
plot([1,2,3], [1,4,9], 'rs', label='line 2')
axis([0, 4, 0, 10])
legend()
If you make multiple lines with one plot command, the kwargs apply
to all those lines, eg
plot(x1, y1, x2, y2, antialising=False)
Neither line will be antialiased.
- plot_date(*args, **kwargs)
- plot_date(d, y, converter, fmt='bo', tz=None, **kwargs)
d is a sequence of dates represented as float days since
0001-01-01 UTC and y are the y values at those dates. fmt is
a plot format string. kwargs are passed on to plot. See plot
for more information.
See matplotlib.dates for helper functions date2num, num2date
and drange for help on creating the required floating point dates
tz is the timezone - defaults to rc value
- plotting()
- Plotting commands
axes - Create a new axes
axis - Set or return the current axis limits
bar - make a bar chart
cla - clear current axes
clf - clear a figure window
close - close a figure window
colorbar - add a colorbar to the current figure
cohere - make a plot of coherence
csd - make a plot of cross spectral density
draw - force a redraw of the current figure
errorbar - make an errorbar graph
figlegend - add a legend to the figure
figimage - add an image to the figure, w/o resampling
figtext - add text in figure coords
figure - create or change active figure
fill - make filled polygons
gca - return the current axes
gcf - return the current figure
gci - get the current image, or None
get - get a handle graphics property
gray - set the current colormap to gray
jet - set the current colormap to jet
hist - make a histogram
hold - set the hold state on current axes
legend - add a legend to the axes
loglog - a log log plot
imread - load image file into array
imshow - plot image data
pcolor - make a pseudocolor plot
plot - make a line plot
psd - make a plot of power spectral density
rc - control the default params
savefig - save the current figure
scatter - make a scatter plot
set - set a handle graphics property
semilogx - log x axis
semilogy - log y axis
show - show the figures
specgram - a spectrogram plot
stem - make a stem plot
subplot - make a subplot (numrows, numcols, axesnum)
table - add a table to the axes
text - add some text at location x,y to the current axes
title - add a title to the current axes
xlabel - add an xlabel to the current axes
ylabel - add a ylabel to the current axes
- psd(x, NFFT=256, Fs=2, detrend=<function detrend_none>, window=<function window_hanning>, noverlap=0)
- The power spectral density by Welches average periodogram method.
The vector x is divided into NFFT length segments. Each segment
is detrended by function detrend and windowed by function window.
noperlap gives the length of the overlap between segments. The
absolute(fft(segment))**2 of each segment are averaged to compute Pxx,
with a scaling to correct for power loss due to windowing. Fs is
the sampling frequency.
-- NFFT must be a power of 2
-- detrend and window are functions, unlike in matlab where they
are vectors. For detrending you can use detrend_none,
detrend_mean, detrend_linear or a custom function. For
windowing, you can use window_none, window_hanning, or a custom
function
-- if length x < NFFT, it will be zero padded to NFFT
Returns the tuple Pxx, freqs
For plotting, the power is plotted as 10*log10(pxx)) for decibels,
though pxx itself is returned
Refs:
Bendat & Piersol -- Random Data: Analysis and Measurement
Procedures, John Wiley & Sons (1986)
- raise_msg_to_str(msg)
- msg is a return arg from a raise. Join with new lines
- rc(*args, **kwargs)
- Set the current rc params. Group is the grouping for the rc, eg
for lines.linewidth the group is 'lines', for axes.facecolor, the
group is 'axes', and so on. kwargs is a list of attribute
name/value pairs, eg
rc('lines', linewidth=2, color='r')
sets the current rc params and is equivalent to
rcParams['lines.linewidth'] = 2
rcParams['lines.color'] = 'r'
The following aliases are available to save typing for interactive
users
'lw' : 'linewidth'
'ls' : 'linestyle'
'c' : 'color'
'fc' : 'facecolor'
'ec' : 'edgecolor'
'mfc' : 'markerfacecolor'
'mec' : 'markeredgecolor'
'mew' : 'markeredgewidth'
'aa' : 'antialiased'
'l' : 'lines'
'a' : 'axes'
'f' : 'figure'
'p' : 'patches'
'g' : 'grid'
Thus you could abbreviate the above rc command as
rc('l', lw=2, c='r')
Note you can use python's kwargs dictionary facility to store
dictionaries of default parameters. Eg, you can customize the
font rc as follows
font = {'family' : 'monospace',
'weight' : 'bold',
'size' : 'larger',
}
rc('font', **font) # pass in the font dict as kwargs
This enables you to easily switch between several configurations.
Use rcdefaults to restore the default rc params after changes.
- rcdefaults()
- Restore the default rc params - the ones that were created at
matplotlib load time
- reshape(...)
- reshape(a, (d1, d2, ..., dn)). Change the shape of a to be an n-dimensional array with dimensions given by d1...dn. Note: the size specified for the new array must be exactly equal to the size of the old one or an error will occur.
- save(fname, X, fmt='%1.4f')
- Save the data in X to file fname using fmt string to convert the
data to strings
fname can be a filename or a file handle
Example usage:
save('test.out', X) # X is an array
save('test1.out', (x,y,z)) # x,y,z equal sized 1D arrays
save('test2.out', x) # x is 1D
save('test3.out', x, fmt='%1.4e') # use exponential notation
- savefig(*args, **kwargs)
- def savefig(fname, dpi=150, facecolor='w', edgecolor='w',
orientation='portrait'):
Save the current figure to filename fname. dpi is the resolution
in dots per inch.
Output file types currently supported are jpeg and png and will be
deduced by the extension to fname
facecolor and edgecolor are the colors os the figure rectangle
orientation is either 'landscape' or 'portrait' - not supported on
all backends; currently only on postscript output.
- scatter(*args, **kwargs)
- SCATTER(x, y) - make a scatter plot of x vs y
SCATTER(x, y, s) - make a scatter plot of x vs y with size in area
given by s
SCATTER(x, y, s, c) - make a scatter plot of x vs y with size in area
given by s and colors given by c
SCATTER(x, y, s, c, **kwargs) - control colormapping and scaling with
keyword args; see below
Make a scatter plot of x versus y. s is a size in points^2 a scalar
or an array of the same length as x or y. c is a color and can be a
single color format string or an length(x) array of intensities which
will be mapped by the matplotlib.colors.colormap instance cmap
The marker can be one of
's' : square
'o' : circle
'^' : triangle up
'>' : triangle right
'v' : triangle down
'<' : triangle left
'd' : diamond
'p' : pentagram
'h' : hexagon
'8' : octagon
s is a size argument in points squared.
Other keyword args; the color mapping and normalization arguments will
on be used if c is an array of floats
* cmap = cm.jet : a cm Colormap instance from matplotlib.cm.
defaults to rc image.cmap
* norm = normalize() : matplotlib.colors.normalize is used to
scale luminance data to 0,1.
* vmin=None and vmax=None : vmin and vmax are used in conjunction
with norm to normalize luminance data. If either are None, the
min and max of the color array C is used. Note if you pass a norm
instance, your settings for vmin and vmax will be ignored
* alpha =1.0 : the alpha value for the patches
- scatter_classic(*args, **kwargs)
- scatter_classic(self, x, y, s=None, c='b'):
Make a scatter plot of x versus y. s is a size (in data
coords) and can be either a scalar or an array of the same
length as x or y. c is a color and can be a single color
format string or an length(x) array of intensities which will
be mapped by the colormap jet.
If size is None a default size will be used
- searchsorted = binarysearch(...)
- binarysearch(a,v)
- semilogx(*args, **kwargs)
- Make a semilog plot with log scaling on the x axis. The args
to semilog x are the same as the args to plot. See help plot
for more info.
Optional keyword args supported are any of the kwargs
supported by plot or set_xscale. Notable, for log scaling:
basex: base of the logarithm
subsx: the location of the minor ticks; None defaults to range(2,basex)
- semilogy(*args, **kwargs)
- Make a semilog plot with log scaling on the y axis. The args to
semilogy are the same as the args to plot. See help plot for
more info.
Optional keyword args supported are any of the kwargs
supported by plot or set_yscale. Notable, for log scaling:
basey: base of the logarithm
subsy: the location of the minor ticks; None defaults to range(2,basey)
- set(h, *args, **kwargs)
- Set handle h property in string s to value val
h can be a handle or vector of handles.
h is an instance (or vector of instances) of a class, eg a Line2D
or an Axes or Text.
args is a list of string, value pairs. if the string
is 'somename', set function calls
o.set_somename(value)
for every instance in h.
- specgram(*args, **kwargs)
- Compute a spectrogram of data in x. Data are split into NFFT
length segements and the PSD of each section is computed. The
windowing function window is applied to each segment, and the
amount of overlap of each segment is specified with noverlap
See help(psd) for information on the other arguments
cmap is a colormap; if None use default determined by rc
return value is Pxx, freqs, bins, im
bins are the time points the spectrogram is calculated over
freqs is an array of frequencies
Pxx is a len(times) x len(freqs) array of power
im is a matplotlib image
xextent is the image extent in the xaxes xextent=xmin, xmax -
default 0, max(bins), 0, max(freqs) where bins is the
return value from matplotlib.mlab.specgram
- stem(*args, **kwargs)
- stem(x, y, linefmt='b-', markerfmt='bo', basefmt='r-')
A stem plot plots vertical lines (using linefmt) at each x
location from the baseline to y, and places a marker there using
markerfmt. A horizontal line at 0 is is plotted using basefmt
return value is markerline, stemlines, baseline
See
http://www.mathworks.com/access/helpdesk/help/techdoc/ref/stem.html
for details and examples/stem_plot.py for a demo.
- subplot(*args, **kwargs)
- Create a subplot command, creating axes with
subplot(numRows, numCols, plotNum)
where plotNum=1 is the first plot number and increasing plotNums
fill rows first. max(plotNum)==numRows*numCols
You can leave out the commas if numRows<=numCols<=plotNum<10, as
in
subplot(211) # 2 rows, 1 column, first (upper) plot
subplot(111) is the default axis
The background color of the subplot can be specified via keyword
argument 'axisbg', which takes a color string or gdk.Color as value, as in
subplot(211, axisbg='y')
- table(*args, **kwargs)
- table(cellText=None, cellColours=None,
cellLoc='right', colWidths=None,
rowLabels=None, rowColours=None, rowLoc='left',
colLabels=None, colColours=None, colLoc='center',
loc='bottom', bbox=None):
Add a table to the current axes. Returns a table instance. For
finer grained control over tables, use the Table class and add it
to the axes with add_table.
Thanks to John Gill for providing the class and table.
- take(...)
- take(a, indices, axis=0). Selects the elements in indices from array a along the given axis.
- text(x, y, label, fontdict=None, **kwargs)
- Add text to axis at location x,y
fontdict is a dictionary to override the default text properties.
If fontdict is None, the default is
'fontsize' : 'x-small',
'verticalalignment' : 'bottom',
'horizontalalignment' : 'left'
**kwargs can in turn be used to override the fontdict, as in
a.text(x,y,label, fontsize='medium')
This command supplies no override dict, and so will have
'verticalalignment'='bottom' and 'horizontalalignment'='left' but
the keyword arg 'fontsize' will create a fontsize of medium or 12
The purpose these options is to make it easy for you to create a
default font theme for your plots by creating a single dictionary,
and then being able to selective change individual attributes for
the varous text creation commands, as in
fonts = {
'color' : 'k',
'fontname' : 'Courier',
'fontweight' : 'bold'
}
title('My title', fonts, fontsize='medium')
xlabel('My xlabel', fonts, fontsize='small')
ylabel('My ylabel', fonts, fontsize='small')
text(12, 20, 'some text', fonts, fontsize='x-small')
The Text defaults are
'color' : 'k',
'fontname' : 'Sans',
'fontsize' : 'small',
'fontweight' : 'bold',
'fontangle' : 'normal',
'horizontalalignment' : 'left'
'rotation' : 'horizontal',
'verticalalignment' : 'bottom',
'transx' : gca().xaxis.transData,
'transy' : gca().yaxis.transData,
transx and transy specify that text is in data coords,
alternatively, you can specify text in axis coords (0,0 lower
left and 1,1 upper right). The example below places text in
the center of the axes
ax = subplot(111)
text(0.5, 0.5,'matplotlib',
horizontalalignment='center',
verticalalignment='center',
transx = ax.xaxis.transAxis,
transy = ax.yaxis.transAxis,
)
- title(s, *args, **kwargs)
- Set the title of the current axis to s
Default font override is:
override = {
'fontsize' : 'medium',
'verticalalignment' : 'bottom',
'horizontalalignment' : 'center'
}
See the text docstring for information of how override and the
optional args work
- vlines(*args, **kwargs)
- lines = vlines(x, ymin, ymax, color='k'):
Plot vertical lines at each x from ymin to ymax. ymin or ymax
can be scalars or len(x) numpy arrays. If they are scalars,
then the respective values are constant, else the heights of
the lines are determined by ymin and ymax
Returns a list of lines that were added
- xlabel(s, *args, **kwargs)
- Set the x axis label of the current axis to s
Default override is
override = {
'fontsize' : 'small',
'verticalalignment' : 'top',
'horizontalalignment' : 'center'
}
See the text docstring for information of how override and
the optional args work
- xlim(*args, **kwargs)
- Set/Get the xlimits of the current axes
xmin, xmax = xlim() : return the current xlim
xlim( (xmin, xmax) ) : set the xlim to xmin, xmax
xlim( xmin, xmax ) : set the xlim to xmin, xmax
- xticks(*args, **kwargs)
- Set/Get the xlimits of the current ticklocs, labels
# return locs, labels where locs is an array of tick locations and
# labels is an array of tick labels.
locs, labels = xticks()
# set the locations of the xticks
xticks( arange(6) )
# set the locations and labels of the xticks
xticks( arange(5), ('Tom', 'Dick', 'Harry', 'Sally', 'Sue') )
- ylabel(s, *args, **kwargs)
- Set the y axis label of the current axis to s
Defaults override is
override = {
'fontsize' : 'small',
'verticalalignment' : 'center',
'horizontalalignment' : 'right',
'rotation'='vertical' : }
See the text docstring for information of how override and the
optional args work
- ylim(*args, **kwargs)
- Set/Get the ylimits of the current axes
ymin, ymax = ylim() : return the current ylim
ylim( (ymin, ymax) ) : set the ylim to ymin, ymax
ylim( ymin, ymax ) : set the ylim to ymin, ymax
- yticks(*args, **kwargs)
- Set/Get the ylimits of the current ticklocs, labels
# return locs, labels where locs is an array of tick locations and
# labels is an array of tick labels.
locs, labels = yticks()
# set the locations of the yticks
yticks( arange(6) )
# set the locations and labels of the yticks
yticks( arange(5), ('Tom', 'Dick', 'Harry', 'Sally', 'Sue') )
- zeros(...)
- zeros((d1,...,dn),typecode='l',savespace=0) will return a new array of shape (d1,...,dn) and type typecode with all it's entries initialized to zero. If savespace is nonzero the array will be a spacesaver array.
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