"""
A collection of utility functions and classes. Many (but not all)
from the Python Cookbook -- hence the name cbook
"""
from __future__ import generators
import re, os, errno, sys, StringIO, traceback, locale
import time, datetime
import numpy as npy
try:
set = set
except NameError:
from sets import Set as set
major, minor1, minor2, s, tmp = sys.version_info
# on some systems, locale.getpreferredencoding returns None, which can break unicode
preferredencoding = locale.getpreferredencoding()
def unicode_safe(s):
if preferredencoding is None: return unicode(s)
else: return unicode(s, preferredencoding)
class converter:
"""
Base class for handling string -> python type with support for
missing values
"""
def __init__(self, missing='Null', missingval=None):
self.missing = missing
self.missingval = missingval
def __call__(self, s):
if s==self.missing: return self.missingval
return s
def is_missing(self, s):
return not s.strip() or s==self.missing
class tostr(converter):
'convert to string or None'
def __init__(self, missing='Null', missingval=''):
converter.__init__(self, missing=missing, missingval=missingval)
class todatetime(converter):
'convert to a datetime or None'
def __init__(self, fmt='%Y-%m-%d', missing='Null', missingval=None):
'use a time.strptime format string for conversion'
converter.__init__(self, missing, missingval)
self.fmt = fmt
def __call__(self, s):
if self.is_missing(s): return self.missingval
tup = time.strptime(s, self.fmt)
return datetime.datetime(*tup[:6])
class todate(converter):
'convert to a date or None'
def __init__(self, fmt='%Y-%m-%d', missing='Null', missingval=None):
'use a time.strptime format string for conversion'
converter.__init__(self, missing, missingval)
self.fmt = fmt
def __call__(self, s):
if self.is_missing(s): return self.missingval
tup = time.strptime(s, self.fmt)
return datetime.date(*tup[:3])
class tofloat(converter):
'convert to a float or None'
def __init__(self, missing='Null', missingval=None):
converter.__init__(self, missing)
self.missingval = missingval
def __call__(self, s):
if self.is_missing(s): return self.missingval
return float(s)
class toint(converter):
'convert to an int or None'
def __init__(self, missing='Null', missingval=None):
converter.__init__(self, missing)
def __call__(self, s):
if self.is_missing(s): return self.missingval
return int(s)
class CallbackRegistry:
"""
Handle registering and disconnecting for a set of signals and
callbacks
signals = 'eat', 'drink', 'be merry'
def oneat(x):
print 'eat', x
def ondrink(x):
print 'drink', x
callbacks = CallbackRegistry(signals)
ideat = callbacks.connect('eat', oneat)
iddrink = callbacks.connect('drink', ondrink)
#tmp = callbacks.connect('drunk', ondrink) # this will raise a ValueError
callbacks.process('drink', 123) # will call oneat
callbacks.process('eat', 456) # will call ondrink
callbacks.process('be merry', 456) # nothing will be called
callbacks.disconnect(ideat) # disconnect oneat
callbacks.process('eat', 456) # nothing will be called
"""
def __init__(self, signals):
'signals is a sequence of valid signals'
self.signals = set(signals)
# callbacks is a dict mapping the signal to a dictionary
# mapping callback id to the callback function
self.callbacks = dict([(s, dict()) for s in signals])
self._cid = 0
def _check_signal(self, s):
'make sure s is a valid signal or raise a ValueError'
if s not in self.signals:
signals = list(self.signals)
signals.sort()
raise ValueError('Unknown signal "%s"; valid signals are %s'%(s, signals))
def connect(self, s, func):
"""
register func to be called when a signal s is generated
func will be called
"""
self._check_signal(s)
self._cid +=1
self.callbacks[s][self._cid] = func
return self._cid
def disconnect(self, cid):
"""
disconnect the callback registered with callback id cid
"""
for eventname, callbackd in self.callbacks.items():
try: del callbackd[cid]
except KeyError: continue
else: return
def process(self, s, *args, **kwargs):
"""
process signal s. All of the functions registered to receive
callbacks on s will be called with *args and **kwargs
"""
self._check_signal(s)
for func in self.callbacks[s].values():
func(*args, **kwargs)
class silent_list(list):
"""
override repr when returning a list of matplotlib artists to
prevent long, meaningless output. This is meant to be used for a
homogeneous list of a give type
"""
def __init__(self, type, seq=None):
self.type = type
if seq is not None: self.extend(seq)
def __repr__(self):
return '<a list of %d %s objects>' % (len(self), self.type)
def __str__(self):
return '<a list of %d %s objects>' % (len(self), self.type)
def strip_math(s):
'remove latex formatting from mathtext'
remove = (r'\mathdefault', r'\rm', r'\cal', r'\tt', r'\it', '\\', '{', '}')
s = s[1:-1]
for r in remove: s = s.replace(r,'')
return s
class Bunch:
"""
Often we want to just collect a bunch of stuff together, naming each
item of the bunch; a dictionary's OK for that, but a small do- nothing
class is even handier, and prettier to use. Whenever you want to
group a few variables:
>>> point = Bunch(datum=2, squared=4, coord=12)
>>> point.datum
By: Alex Martelli
From: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/52308
"""
def __init__(self, **kwds):
self.__dict__.update(kwds)
def unique(x):
'Return a list of unique elements of x'
return dict([ (val, 1) for val in x]).keys()
def iterable(obj):
try: len(obj)
except: return 0
return 1
def is_string_like(obj):
if hasattr(obj, 'shape'): return 0
try: obj + ''
except (TypeError, ValueError): return 0
return 1
def is_writable_file_like(obj):
return hasattr(obj, 'write') and callable(obj.write)
def is_scalar(obj):
return is_string_like(obj) or not iterable(obj)
def is_numlike(obj):
try: obj+1
except TypeError: return False
else: return True
def to_filehandle(fname, flag='r'):
"""
fname can be a filename or a file handle. Support for gzipped
files is automatic, if the filename ends in .gz. flag is a
read/write flag for file
"""
if is_string_like(fname):
if fname.endswith('.gz'):
import gzip
fh = gzip.open(fname, flag)
else:
fh = file(fname, flag)
elif hasattr(fname, 'seek'):
fh = fname
else:
raise ValueError('fname must be a string or file handle')
return fh
def flatten(seq, scalarp=is_scalar):
"""
this generator flattens nested containers such as
>>> l=( ('John', 'Hunter'), (1,23), [[[[42,(5,23)]]]])
so that
>>> for i in flatten(l): print i,
John Hunter 1 23 42 5 23
By: Composite of Holger Krekel and Luther Blissett
From: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/121294
and Recipe 1.12 in cookbook
"""
for item in seq:
if scalarp(item): yield item
else:
for subitem in flatten(item, scalarp):
yield subitem
class Sorter:
"""
Sort by attribute or item
Example usage:
sort = Sorter()
list = [(1, 2), (4, 8), (0, 3)]
dict = [{'a': 3, 'b': 4}, {'a': 5, 'b': 2}, {'a': 0, 'b': 0},
{'a': 9, 'b': 9}]
sort(list) # default sort
sort(list, 1) # sort by index 1
sort(dict, 'a') # sort a list of dicts by key 'a'
"""
def _helper(self, data, aux, inplace):
aux.sort()
result = [data[i] for junk, i in aux]
if inplace: data[:] = result
return result
def byItem(self, data, itemindex=None, inplace=1):
if itemindex is None:
if inplace:
data.sort()
result = data
else:
result = data[:]
result.sort()
return result
else:
aux = [(data[i][itemindex], i) for i in range(len(data))]
return self._helper(data, aux, inplace)
def byAttribute(self, data, attributename, inplace=1):
aux = [(getattr(data[i],attributename),i) for i in range(len(data))]
return self._helper(data, aux, inplace)
# a couple of handy synonyms
sort = byItem
__call__ = byItem
class Xlator(dict):
"""
All-in-one multiple-string-substitution class
Example usage:
text = "Larry Wall is the creator of Perl"
adict = {
"Larry Wall" : "Guido van Rossum",
"creator" : "Benevolent Dictator for Life",
"Perl" : "Python",
}
print multiple_replace(adict, text)
xlat = Xlator(adict)
print xlat.xlat(text)
"""
def _make_regex(self):
""" Build re object based on the keys of the current dictionary """
return re.compile("|".join(map(re.escape, self.keys())))
def __call__(self, match):
""" Handler invoked for each regex match """
return self[match.group(0)]
def xlat(self, text):
""" Translate text, returns the modified text. """
return self._make_regex().sub(self, text)
def soundex(name, len=4):
""" soundex module conforming to Odell-Russell algorithm """
# digits holds the soundex values for the alphabet
soundex_digits = '01230120022455012623010202'
sndx = ''
fc = ''
# Translate letters in name to soundex digits
for c in name.upper():
if c.isalpha():
if not fc: fc = c # Remember first letter
d = soundex_digits[ord(c)-ord('A')]
# Duplicate consecutive soundex digits are skipped
if not sndx or (d != sndx[-1]):
sndx += d
# Replace first digit with first letter
sndx = fc + sndx[1:]
# Remove all 0s from the soundex code
sndx = sndx.replace('0', '')
# Return soundex code truncated or 0-padded to len characters
return (sndx + (len * '0'))[:len]
class Null:
""" Null objects always and reliably "do nothing." """
def __init__(self, *args, **kwargs): pass
def __call__(self, *args, **kwargs): return self
def __str__(self): return "Null()"
def __repr__(self): return "Null()"
def __nonzero__(self): return 0
def __getattr__(self, name): return self
def __setattr__(self, name, value): return self
def __delattr__(self, name): return self
def mkdirs(newdir, mode=0777):
try: os.makedirs(newdir, mode)
except OSError, err:
# Reraise the error unless it's about an already existing directory
if err.errno != errno.EEXIST or not os.path.isdir(newdir):
raise
class GetRealpathAndStat:
def __init__(self):
self._cache = {}
def __call__(self, path):
result = self._cache.get(path)
if result is None:
realpath = os.path.realpath(path)
stat = os.stat(realpath)
stat_key = (stat.st_ino, stat.st_dev)
result = realpath, stat_key
self._cache[path] = result
return result
get_realpath_and_stat = GetRealpathAndStat()
def dict_delall(d, keys):
'delete all of the keys from the dict d'
for key in keys:
try: del d[key]
except KeyError: pass
class RingBuffer:
""" class that implements a not-yet-full buffer """
def __init__(self,size_max):
self.max = size_max
self.data = []
class __Full:
""" class that implements a full buffer """
def append(self, x):
""" Append an element overwriting the oldest one. """
self.data[self.cur] = x
self.cur = (self.cur+1) % self.max
def get(self):
""" return list of elements in correct order """
return self.data[self.cur:]+self.data[:self.cur]
def append(self,x):
"""append an element at the end of the buffer"""
self.data.append(x)
if len(self.data) == self.max:
self.cur = 0
# Permanently change self's class from non-full to full
self.__class__ = __Full
def get(self):
""" Return a list of elements from the oldest to the newest. """
return self.data
def __get_item__(self, i):
return self.data[i % len(self.data)]
# use enumerate builtin if available, else use python version
try:
import __builtin__
enumerate = __builtin__.enumerate
except:
def enumerate(seq):
"""Python equivalent to the enumerate builtin function
enumerate() is new in Python 2.3
"""
for i in range(len(seq)):
yield i, seq[i]
# use reversed builtin if available, else use python version
try:
import __builtin__
reversed = __builtin__.reversed
except:
def reversed(seq):
"""Python equivalent to the enumerate builtin function
enumerate() is new in Python 2.3
"""
for i in range(len(seq)-1,-1,-1):
yield seq[i]
# use itertools.izip if available, else use python version
try:
import itertools
izip = itertools.izip
except:
def izip(*iterables):
"""Python equivalent to itertools.izip
itertools module - new in Python 2.3
"""
iterables = map(iter, iterables)
while iterables:
result = [i.next() for i in iterables]
yield tuple(result)
def get_split_ind(seq, N):
"""seq is a list of words. Return the index into seq such that
len(' '.join(seq[:ind])<=N
"""
sLen = 0
# todo: use Alex's xrange pattern from the cbook for efficiency
for (word, ind) in zip(seq, range(len(seq))):
sLen += len(word) + 1 # +1 to account for the len(' ')
if sLen>=N: return ind
return len(seq)
def wrap(prefix, text, cols):
'wrap text with prefix at length cols'
pad = ' '*len(prefix.expandtabs())
available = cols - len(pad)
seq = text.split(' ')
Nseq = len(seq)
ind = 0
lines = []
while ind<Nseq:
lastInd = ind
ind += get_split_ind(seq[ind:], available)
lines.append(seq[lastInd:ind])
# add the prefix to the first line, pad with spaces otherwise
ret = prefix + ' '.join(lines[0]) + '\n'
for line in lines[1:]:
ret += pad + ' '.join(line) + '\n'
return ret
# A regular expression used to determine the amount of space to
# remove. It looks for the first sequence of spaces immediately
# following the first newline, or at the beginning of the string.
_find_dedent_regex = re.compile("(?:(?:\n\r?)|^)( *)\S")
# A cache to hold the regexs that actually remove the indent.
_dedent_regex = {}
def dedent(s):
"""
Remove excess indentation from docstrings.
Discards any leading blank lines, then removes up to
n whitespace characters from each line, where n is
the number of leading whitespace characters in the
first line. It differs from textwrap.dedent in its
deletion of leading blank lines and its use of the
first non-blank line to determine the indentation.
It is also faster in most cases.
"""
# This implementation has a somewhat obtuse use of regular
# expressions. However, this function accounted for almost 30% of
# matplotlib startup time, so it is worthy of optimization at all
# costs.
if not s: # includes case of s is None
return ''
match = _find_dedent_regex.match(s)
if match is None:
return s
# This is the number of spaces to remove from the left-hand side.
nshift = match.end(1) - match.start(1)
if nshift == 0:
return s
# Get a regex that will remove *up to* nshift spaces from the
# beginning of each line. If it isn't in the cache, generate it.
unindent = _dedent_regex.get(nshift, None)
if unindent is None:
unindent = re.compile("\n\r? {0,%d}" % nshift)
_dedent_regex[nshift] = unindent
result = unindent.sub("\n", s).strip()
return result
def listFiles(root, patterns='*', recurse=1, return_folders=0):
"""
Recursively list files
from Parmar and Martelli in the Python Cookbook
"""
import os.path, fnmatch
# Expand patterns from semicolon-separated string to list
pattern_list = patterns.split(';')
# Collect input and output arguments into one bunch
class Bunch:
def __init__(self, **kwds): self.__dict__.update(kwds)
arg = Bunch(recurse=recurse, pattern_list=pattern_list,
return_folders=return_folders, results=[])
def visit(arg, dirname, files):
# Append to arg.results all relevant files (and perhaps folders)
for name in files:
fullname = os.path.normpath(os.path.join(dirname, name))
if arg.return_folders or os.path.isfile(fullname):
for pattern in arg.pattern_list:
if fnmatch.fnmatch(name, pattern):
arg.results.append(fullname)
break
# Block recursion if recursion was disallowed
if not arg.recurse: files[:]=[]
os.path.walk(root, visit, arg)
return arg.results
def get_recursive_filelist(args):
"""
Recurs all the files and dirs in args ignoring symbolic links and
return the files as a list of strings
"""
files = []
for arg in args:
if os.path.isfile(arg):
files.append(arg)
continue
if os.path.isdir(arg):
newfiles = listFiles(arg, recurse=1, return_folders=1)
files.extend(newfiles)
return [f for f in files if not os.path.islink(f)]
def pieces(seq, num=2):
"Break up the seq into num tuples"
start = 0
while 1:
item = seq[start:start+num]
if not len(item): break
yield item
start += num
def exception_to_str(s = None):
sh = StringIO.StringIO()
if s is not None: print >>sh, s
traceback.print_exc(file=sh)
return sh.getvalue()
def allequal(seq):
"""
return true if all elements of seq compare equal. If seq is 0 or
1 length, return True
"""
if len(seq)<2: return True
val = seq[0]
for i in xrange(1, len(seq)):
thisval = seq[i]
if thisval != val: return False
return True
def alltrue(seq):
#return true if all elements of seq are true. If seq is empty return false
if not len(seq): return False
for val in seq:
if not val: return False
return True
def onetrue(seq):
#return true if one element of seq is true. If seq is empty return false
if not len(seq): return False
for val in seq:
if val: return True
return False
def allpairs(x):
"""
return all possible pairs in sequence x
Condensed by Alex Martelli from this thread on c.l.python
http://groups.google.com/groups?q=all+pairs+group:*python*&hl=en&lr=&ie=UTF-8&selm=mailman.4028.1096403649.5135.python-list%40python.org&rnum=1
"""
return [ (s, f) for i, f in enumerate(x) for s in x[i+1:] ]
# python 2.2 dicts don't have pop--but we don't support 2.2 any more
def popd(d, *args):
"""
Should behave like python2.3 pop method; d is a dict
# returns value for key and deletes item; raises a KeyError if key
# is not in dict
val = popd(d, key)
# returns value for key if key exists, else default. Delete key,
# val item if it exists. Will not raise a KeyError
val = popd(d, key, default)
"""
if len(args)==1:
key = args[0]
val = d[key]
del d[key]
elif len(args)==2:
key, default = args
val = d.get(key, default)
try: del d[key]
except KeyError: pass
return val
class maxdict(dict):
"""
A dictionary with a maximum size; this doesn't override all the
relevant methods to contrain size, just setitem, so use with
caution
"""
def __init__(self, maxsize):
dict.__init__(self)
self.maxsize = maxsize
self._killkeys = []
def __setitem__(self, k, v):
if len(self)>=self.maxsize:
del self[self._killkeys[0]]
del self._killkeys[0]
dict.__setitem__(self, k, v)
self._killkeys.append(k)
class Stack:
"""
Implement a stack where elements can be pushed on and you can move
back and forth. But no pop. Should mimic home / back / forward
in a browser
"""
def __init__(self, default=None):
self.clear()
self._default = default
def __call__(self):
'return the current element, or None'
if not len(self._elements): return self._default
else: return self._elements[self._pos]
def forward(self):
'move the position forward and return the current element'
N = len(self._elements)
if self._pos<N-1: self._pos += 1
return self()
def back(self):
'move the position back and return the current element'
if self._pos>0: self._pos -= 1
return self()
def push(self, o):
"""
push object onto stack at current position - all elements
occurring later than the current position are discarded
"""
self._elements = self._elements[:self._pos+1]
self._elements.append(o)
self._pos = len(self._elements)-1
return self()
def home(self):
'push the first element onto the top of the stack'
if not len(self._elements): return
self.push(self._elements[0])
return self()
def empty(self):
return len(self._elements)==0
def clear(self):
'empty the stack'
self._pos = -1
self._elements = []
def bubble(self, o):
"""
raise o to the top of the stack and return o. o must be in
the stack
"""
if o not in self._elements:
raise ValueError('Unknown element o')
old = self._elements[:]
self.clear()
bubbles = []
for thiso in old:
if thiso==o: bubbles.append(thiso)
else: self.push(thiso)
for thiso in bubbles:
self.push(o)
return o
def remove(self, o):
'remove element o from the stack'
if o not in self._elements:
raise ValueError('Unknown element o')
old = self._elements[:]
self.clear()
for thiso in old:
if thiso==o: continue
else: self.push(thiso)
def popall(seq):
'empty a list'
for i in xrange(len(seq)): seq.pop()
def finddir(o, match, case=False):
"""
return all attributes of o which match string in match. if case
is True require an exact case match.
"""
if case:
names = [(name,name) for name in dir(o) if is_string_like(name)]
else:
names = [(name.lower(), name) for name in dir(o) if is_string_like(name)]
match = match.lower()
return [orig for name, orig in names if name.find(match)>=0]
def reverse_dict(d):
'reverse the dictionary -- may lose data if values are not uniq!'
return dict([(v,k) for k,v in d.items()])
def report_memory(i=0): # argument may go away
'return the memory consumed by process'
pid = os.getpid()
if sys.platform=='sunos5':
a2 = os.popen('ps -p %d -o osz' % pid).readlines()
mem = int(a2[-1].strip())
elif sys.platform.startswith('linux'):
a2 = os.popen('ps -p %d -o rss,sz' % pid).readlines()
mem = int(a2[1].split()[1])
elif sys.platform.startswith('darwin'):
a2 = os.popen('ps -p %d -o rss,vsz' % pid).readlines()
mem = int(a2[1].split()[0])
return mem
_safezip_msg = 'In safezip, len(args[0])=%d but len(args[%d])=%d'
def safezip(*args):
'make sure args are equal len before zipping'
Nx = len(args[0])
for i, arg in enumerate(args[1:]):
if len(arg) != Nx:
raise ValueError(_safezip_msg % (Nx, i+1, len(arg)))
return zip(*args)
class MemoryMonitor:
def __init__(self, nmax=20000):
self._nmax = nmax
self._mem = npy.zeros((self._nmax,), npy.int32)
self.clear()
def clear(self):
self._n = 0
self._overflow = False
def __call__(self):
mem = report_memory()
if self._n < self._nmax:
self._mem[self._n] = mem
self._n += 1
else:
self._overflow = True
return mem
def report(self, segments=4):
n = self._n
segments = min(n, segments)
dn = int(n/segments)
ii = range(0, n, dn)
ii[-1] = n-1
print
print 'memory report: i, mem, dmem, dmem/nloops'
print 0, self._mem[0]
for i in range(1, len(ii)):
di = ii[i] - ii[i-1]
if di == 0:
continue
dm = self._mem[ii[i]] - self._mem[ii[i-1]]
print '%5d %5d %3d %8.3f' % (ii[i], self._mem[ii[i]],
dm, dm / float(di))
if self._overflow:
print "Warning: array size was too small for the number of calls."
def xy(self, i0=0, isub=1):
x = npy.arange(i0, self._n, isub)
return x, self._mem[i0:self._n:isub]
def plot(self, i0=0, isub=1, fig=None):
if fig is None:
from pylab import figure, show
fig = figure()
ax = fig.add_subplot(111)
ax.plot(*self.xy(i0, isub))
fig.canvas.draw()
def print_cycles(objects, outstream=sys.stdout, show_progress=False):
"""
objects: A list of objects to find cycles in. It is often useful
to pass in gc.garbage to find the cycles that are
preventing some objects from being garbage collected.
outstream: The stream for output.
show_progress: If True, print the number of objects reached as they are
found.
"""
import gc
from types import FrameType
def print_path(path):
for i, step in enumerate(path):
# next "wraps around"
next = path[(i + 1) % len(path)]
outstream.write(" %s -- " % str(type(step)))
if isinstance(step, dict):
for key, val in step.items():
if val is next:
outstream.write("[%s]" % repr(key))
break
if key is next:
outstream.write("[key] = %s" % repr(val))
break
elif isinstance(step, list):
outstream.write("[%d]" % step.index(next))
elif isinstance(step, tuple):
outstream.write("( tuple )")
else:
outstream.write(repr(step))
outstream.write(" ->\n")
outstream.write("\n")
def recurse(obj, start, all, current_path):
if show_progress:
outstream.write("%d\r" % len(all))
all[id(obj)] = None
referents = gc.get_referents(obj)
for referent in referents:
# If we've found our way back to the start, this is
# a cycle, so print it out
if referent is start:
print_path(current_path)
# Don't go back through the original list of objects, or
# through temporary references to the object, since those
# are just an artifact of the cycle detector itself.
elif referent is objects or isinstance(referent, FrameType):
continue
# We haven't seen this object before, so recurse
elif id(referent) not in all:
recurse(referent, start, all, current_path + [obj])
for obj in objects:
outstream.write("Examining: %r\n" % (obj,))
recurse(obj, obj, { }, [])
class Grouper(object):
"""
This class provides a lightweight way to group arbitrary objects
together into disjoint sets when a full-blown graph data structure
would be overkill.
Objects can be joined using .join(), tested for connectedness
using .joined(), and all disjoint sets can be retreived using
.get().
The objects being joined must be hashable.
For example:
>>> g = grouper.Grouper()
>>> g.join('a', 'b')
>>> g.join('b', 'c')
>>> g.join('d', 'e')
>>> list(g.get())
[['a', 'b', 'c'], ['d', 'e']]
>>> g.joined('a', 'b')
True
>>> g.joined('a', 'c')
True
>>> g.joined('a', 'd')
False
"""
def __init__(self, init=[]):
mapping = self._mapping = {}
for x in init:
mapping[x] = [x]
def __contains__(self, item):
return item in self._mapping
def join(self, a, *args):
"""
Join given arguments into the same set.
Accepts one or more arguments.
"""
mapping = self._mapping
set_a = mapping.setdefault(a, [a])
for arg in args:
set_b = mapping.get(arg)
if set_b is None:
set_a.append(arg)
mapping[arg] = set_a
elif set_b is not set_a:
if len(set_b) > len(set_a):
set_a, set_b = set_b, set_a
set_a.extend(set_b)
for elem in set_b:
mapping[elem] = set_a
def joined(self, a, b):
"""
Returns True if a and b are members of the same set.
"""
mapping = self._mapping
try:
return mapping[a] is mapping[b]
except KeyError:
return False
def __iter__(self):
"""
Returns an iterator yielding each of the disjoint sets as a list.
"""
seen = set()
for elem, group in self._mapping.iteritems():
if elem not in seen:
yield group
seen.update(group)
def get_siblings(self, a):
"""
Returns all of the items joined with the given item, including
itself.
"""
return self._mapping.get(a, [a])
def simple_linear_interpolation(a, steps):
steps = npy.floor(steps)
new_length = ((len(a) - 1) * steps) + 1
new_shape = list(a.shape)
new_shape[0] = new_length
result = npy.zeros(new_shape, a.dtype)
result[0] = a[0]
a0 = a[0:-1]
a1 = a[1: ]
delta = ((a1 - a0) / steps)
for i in range(1, int(steps)):
result[i::steps] = delta * i + a0
result[steps::steps] = a1
return result
if __name__=='__main__':
assert( allequal([1,1,1]) )
assert(not allequal([1,1,0]) )
assert( allequal([]) )
assert( allequal(('a', 'a')))
assert( not allequal(('a', 'b')))
