In This Article, You Will Learn About Python Variables.
Python Variables – In Python, variable is the location where a programmer or developer store value. In another words, variables are firstly created when you assign a value to it. Unlike other programming languages, Python has no command for declaring a variable.
Python can accept following type of variable –
1. Letter can be upper case (A-Z) and lower case (a-z). It should be noted that variable must be begin with letters. It can also have underscore (_).
2. Value can be string, number (int and float) and Boolean value (True and False).
Note: Python variable case is sensitive be careful regarding it. There are some variables name or reserved words which has already been reserved by Python so we can’t use them.
The basic syntax of Python Variable is –
<variable> = <expression>
Int_number = 1 string = "codingstreets" float_number = 1.2 Boolean = True print(Int_number) print(string) print(float_number) print(Boolean)
Note: Where, equal sign (=) is used to assign a value (right side) to a variable name (left side).
In Python, A variable can have short name like a and h and it can have a long or descriptive name such as mystery, qualifications and my_name etc. In nut shell, a variable name must be started with a letter (a,b) or the underscore character (my_name) and it contains only alpha numeric characters and underscores (A-z, 0-9, and _ ).
myname = "Alex" Myname = "Alex" my_name = "Alex" print(myname) print(Myname) print(my_name)
Here are some examples based on variable which can be used to assign a value to a variable name.
Uppercase with underscore(_)
Lowercase with underscore(_)
String Integer or Int Float (generally in mathematical term it is referred as decimal number)
my_file “X”, “Alex”, “hello python world”, “z” etc. 1,27,6,5 etc. 65.7, 4.0, 6.1 etc.
Single or Double Quotes
In Python, variable can be written in both single quote (‘’) and double quote (“”) and value of variable will be same in both quotes.
Str = "codingstreets" # meaning of the variable will be same Str = 'codingstreets' print(Str)
In Python, a variable type can get by using type() function.
Int = 2 Str = "codingstreets" print(type(Int)) print(type(Str))
As Python considers the latest value of a variable therefore, a variable with same name’s value gets change or update automatically. In other words, changing a variable data type into other data type.
Int_number = 1 # Int_number is int. Int_number = "codingstreets" # Int_number is string. print(Int_number)
Specifying a data type of variable is known as Casting.
Str = str(3) # Str will be '3' Int = int(3) # Int will be 3 Float = float(3) # Float will be 3.0 print(Str) print(Int) print(Float)
In Python, variables name is case sensitive.
x = "codingstreets" print(X)
Note: Be careful! Python Variable case is sensitive. If lowercase variable (add) change into uppercase variable (Add) and capitalization (ADD) then Python will give us an error.
Assign Value to Multiple Variables
In Python, you can assign values to multiple variables in one line:
x,y,z = "Alex", "Sara", "Thomas" print (x) print (y) print (z)
In Python, to combine variable you can use (+) operator.
x = "programmer" print("I am a " + x )
(+) operator also can be used to add variables.
x = "I like to read articles" z = "on codingstreets.com" print(x+z)
x = 20 z = 5 print(x+z)
Note: Python will give us an error, if you try to add string and number.
name = "Alex" age = 20 print(name+age)
Global Variables – Variable which are created outside the function it’s called global variables. Like in above all examples variable was created outside the function.
Global variables can be used in both inside and outside of functions.
Create a variable outside of a function, and use it inside the function.
name = "I am Alex." def myfunc(): print(name) myfunc()
If you create a variable with the same name inside a function, then variable will be local, and can only be used inside the function. The global variable with the same name will remain as it was, global and with the original value.
Create a variable inside a function, with the same name as the global or outside variable.
name = "I am Alex." def myfun(): name = "I am Elisa." print(name) myfunc() print(name)
The global Keyword – Normally, when a variable is created inside function, it works as local variable and can be used only inside the function. To use variable as global inside function, use global keyword.
Use the global keyword, the variable belongs to the global scope:
def myfunc(): global name name = "I am Elisa." myfunc() print(name)
Also, use the global keyword to change a global variable inside a function.
name = "I am Alex." def myfunc(): global name name = "I am Elisa." myfunc() print(name)
If you find anything incorrect in above discussed topic and have any further question, please comment down below.