Python Programming Introduction demo.ppt

Introduction to Programming Language
(Python)

• Programming languages are essential tools used to
communicate instructions to computers.
• They bridge the gap between human-readable code
and machine-executable instructions.

Computer Languages
• Machine Language
• Uses binary code
• Machine-dependent
• Not portable
• Assembly Language
– Uses mnemonics
– Machine-dependent
– Not usually portable
• High-Level Language (HLL)
– Uses English-like language
– Machine independent
– Portable (but must be compiled for different platforms)
– Examples: Python, C, C++, Java, Fortran, . . .

Compilation
• Compiler translates source into target (a machine language
program)
• Compiler goes away at execution time
• Compiler is itself a machine language program
Compiler
Target Program
Source
Program
Target
Program
Input Output

Program Execution
• Steps taken by the CPU to run a program
(instructions are in machine language):
1. Fetch an instruction
2. Decode (interpret) the instruction
3. Retrieve data, if needed
4. Execute (perform) actual processing
5. Store the results, if needed

Write/Edit
Run
with some input
OK?
YES
More
Inputs?
YES
NO
NO
Program Cycle

Program Errors
• Syntax Errors:
– Errors in grammar of the language
• Runtime error:
– When there are no syntax errors, but the program can’t
complete execution
• Divide by zero
• Invalid input data
• Logical errors:
– The program completes execution, but delivers incorrect
results
– Incorrect usage of parentheses

How to use Python in your PC
• You can install the python software from
http://python.org/downloads/
• You can use the Python IDE (integrated development
environment) like PyCharm, Anaconda, Jupiter
notebook, etc.
• You can use online Python compiler like
www.onlinegdb.com

Ways to run the Python program
1. Running Python in interactive mode:

2. Running Python in script mode:
User Program
Filename as Hello with extension as py

• Working with the interactive mode is better when
Python programmers deal with small pieces of code
as you can type and execute them immediately, but
when the code is more than 2-4 lines, using the script
for coding can help to modify and use the code in
future

x,y = 6,10
if x < y:
print (x)
else:
print (y)
print (‘is the min’)
x y
6 10
Run the program
Output
6
Indentation
• Indentation is important in Python
– grouping of statement (block of statements)
– no explicit brackets, e.g. { }, to group statements
skipped

INPUT ( ) FUNCTION
INPUT ( ) FUNCTION

INPUT ( ) FUNCTION
INPUT ( ) FUNCTION
Input( ) Function is a built in function of
Input( ) Function is a built in function of
python used to read values from the user as a
python used to read values from the user as a
string type.
string type.
The general format or syntax of the input() is:
variableName =input(message)
variableName =input(message)
For Example:
For Example:
Where,
Where,
variableName
variableName is a variable which is the label
is a variable which is the label
for a memory location where the value is
for a memory location where the value is
stored.
stored.

INPUT ( ) FUNCTION
INPUT ( ) FUNCTION
For Example:
For Example:
p = input(“Enter the value”)
p = input(“Enter the value”)
Note: it will read the value as string (non-numeric).
Note: it will read the value as string (non-numeric).
x = int(input(“Enter x value”))
x = int(input(“Enter x value”))
reads the value and converts it in to integer type
reads the value and converts it in to integer type
data or value.
data or value.
y=float(input(“Enter y value”))
y=float(input(“Enter y value”))
reads the value and converts it in to float type
reads the value and converts it in to float type
data or value.
data or value.

INPUT ( ) FUNCTION
INPUT ( ) FUNCTION
int ( ) and float ( ) Functions:
int ( ) and float ( ) Functions:
Python offers two functions to be used
Python offers two functions to be used
with input( ) to convert the received values:
with input( ) to convert the received values:
Example 1:
Example 1: >>age = int(input(“Enter age”))
>>age = int(input(“Enter age”))
Example 2:
Example 2: >>sal=float(input(“Enter salary))
>>sal=float(input(“Enter salary))

PRINT ( ) FUNCTION
PRINT ( ) FUNCTION

PRINT ( ) FUNCTION
PRINT ( ) FUNCTION
print( )
print( ) Function is a built in function of
Function is a built in function of
python used to display the values on the
python used to display the values on the
screen
screen
Print(“message”, variable)
Print(“message”, variable)
The print function can print an arbitrary
The print function can print an arbitrary
number of values ("value1, value2, ..."), which are
number of values ("value1, value2, ..."), which are
separated by commas. These values are separated
separated by commas. These values are separated
by blanks. In the following example we can see
by blanks. In the following example we can see
two print calls. We are printing two values in both
two print calls. We are printing two values in both
cases, i.e. a string and a float number:
cases, i.e. a string and a float number:

PRINT ( ) FUNCTION
PRINT ( ) FUNCTION
print("Python is fun.")
print("Python is fun.")
a = 5
a = 5
#Two objects are passed:
#Two objects are passed:
print("a =", a)
print("a =", a)
b = a
b = a
# Three objects are passed:
# Three objects are passed:
print('a =', a, '= b‘)
print('a =', a, '= b‘)
Output
Output
Python is fun.
Python is fun.
a = 5
a = 5
a = 5 = b
a = 5 = b
Example 1: How print() works in Python?

PRINT ( ) FUNCTION
PRINT ( ) FUNCTION
>>> print("a = ", a)
>>> print("a = ", a)
a = 3.564
a = 3.564
>>> print("a = n", a)
>>> print("a = n", a)
a =
a =
3.564
3.564
>>>
>>>

Simple problems in Python:
• Print “Hello Word!”
• Add two integer numbers
• Multiplication of two numbers.
• Compute average of 3 numbers.
• Find area of rectangle.
• Find area of square
• Find area of circle
• Find perimeter of rectangle.

Any Questions Please
Any Questions Please

Python Programming Introduction demo.ppt

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