(B15) Python part2 Variables, Assign a Varaible, Input variable, output variable print statements

20220330 120505
Variables are containers for storing data values.

a=12

b=34.5

c='Hyderabad'

Name="Latif"

Age=33
-----------------
a=12
a
12
print(a)
12
print("a")
a
type(a)
class 'int'
print(type(a))
class 'int'
b=34.5
print(b)
34.5
print(type(b))
class 'float'
c="Hyderabad"
print(c)
Hyderabad
print(type(c))
class 'str'
-----------------------
Variable Names
A variable can have a short name (like x and y) or a more descriptive name (age, carname, total_volume). Rules for Python variables:
A variable name must start with a letter or the underscore character
A variable name cannot start with a number
A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
Variable names are case-sensitive (age, Age and AGE are three different variables)
Example
Legal variable names:

myvar = "John"
my_var = "John"
_my_var = "John"
myVar = "John"
MYVAR = "John"
myvar2 = "John"

Example
Illegal variable names:

2myvar = "John"
my-var = "John"
my var = "John"
----------------------------------
a
12
A=22
a
12
A
22
name='priyanka'
Name='Binod'
name
'priyanka'
Name
'Binod'
B14_Name='Aniketh'
_b15_name='Gayathri'
_15name_='latif'
15name='nithesh'
SyntaxError: invalid decimal literal
batch_ = 15
batch_
15
b15-age
Traceback (most recent call last):

b15-age
NameError: name 'b15' is not defined
b15-age=22
SyntaxError: cannot assign to expression here. Maybe you meant '==' instead of '='?
name age=22
SyntaxError: invalid syntax
name1='praful'
age^=44
Traceback (most recent call last):

age^=44
NameError: name 'age' is not defined
----------------------------------
Camel Case
Each word, except the first, starts with a capital letter:

myVariableName = "John"

Pascal Case
Each word starts with a capital letter:

MyVariableName = "John"

Snake Case
Each word is separated by an underscore character:

my_variable_name = "John"

---
myFirstName='latif'
MyAddress="Pune"
My_Age_2022=34
--------------------------------
Assign Multiple Values

Many Values to Multiple Variables
Python allows you to assign values to multiple variables in one line:

Example
x, y, z = "Orange", "Banana", "Cherry"
print(x)
print(y)
print(z)
-------
a,b,c=33,44,55
a
33
b
44
c
55
-------
One Value to Multiple Variables
And you can assign the same value to multiple variables in one line:

Example
x = y = z = "Orange"
print(x)
print(y)
print(z)
------------
a=b=c=65
a
65
b
65
c
65
--------------
Unpack a Collection
If you have a collection of values in a list, tuple etc. Python allows you to extract the values into variables. This is called unpacking.

Example
Unpack a list:

fruits = ["apple", "banana", "cherry"]
x, y, z = fruits
print(x)
print(y)
print(z)
-----------------------------------
a
65
b
65
print(a)
65
print('a=', a)
a= 65
print('a and b', a,b)
a and b 65 65
print('a+b', a+b)
a+b 130
print('a+b=',a+b)
a+b= 130
print('a=',a,'b=',b)
a= 65 b= 65
c
65
print('Hello How are you')
Hello How are you
print("Hello How are you")
Hello How are you
print('Hello,"Manoj" How are you')
Hello,"Manoj" How are you
print("Hello,'Manoj'How are you")
Hello,'Manoj'How are you
print('Hello,"Manoj" \nHow are you')
Hello,"Manoj"
How are you
print('''This is writing a paragraph
i am using python from 4 years
learn python is easy
python is platform independent''')
This is writing a paragraph
i am using python from 4 years
learn python is easy
python is platform independent
print("""This is writing a paragraph
i am using python from 4 years
learn python is easy
python is platform independent""")
This is writing a paragraph
i am using python from 4 years
learn python is easy
python is platform independent
a
65
a=20
b="Banu"
print(f"My Name is {b}, Age is {a}")
My Name is Banu, Age is 20
----------------------------------------------
Input

raw_input -py2

x=input()
22
print(x)
22
x=input('Enter x=')
Enter x=33
print(x)
33
type(x)
class 'str'
x+2
Traceback (most recent call last):

x+2
TypeError: can only concatenate str (not "int") to str
"my age"+x
'my age33'


y=int(input('y='))
y=44

print(y)
44
print(type(y))
class 'int'
y+2
46
"my age"+y
Traceback (most recent call last):

"my age"+y
TypeError: can only concatenate str (not "int") to str
---------------------------------------
z=str(input("z="))

z=555
type(z)

class 'str'
x+z

'33555'
x

'33'
z

'555'
------------------------------