Variable is a name for a location in memory. It can be used to hold a value and reference that stored value within a computer program. the interpreter allocates memory and decides what can be stored in the reserved memory. Therefore, by assigning different data types to the variables, you can store integers, strings, decimals, complex in these variables. The assignment operator in Python 3 is a single equals sign (=). This operator assigns the value on the right-hand side to the variable on the left-hand side.
Example 1 : Assign value in a variable:
# this is a integer type variable number = 123456 # this is a string type variable sentence = "this is a string" # print integer print(number) # print string print(sentence) |
123456 this is a string
Example 2 : Multiple Assignment : Python allows us to assign one single value to several variables at the same time
# assign single value to multiple variables a = b = c = d = e = 123 # print a print(a) # print b print(b) # print c print(c) # print d print(d) # print e print(e) |
123 123 123 123 123
An integer is created with the value 123, and all the five variables such as ( a b c d e ) are assigned to the same memory location.
Example 3 : Assign multiple objects to multiple variables :
# assign multiple objects to multiple variables var1, var2, var3 = 123, 5.0, "this is string" # print var2 print(var1) # print var2 print(var2) # print var3 print(var3) |
123 5.0 this is string
An integer objects var1 with values 123, a decimal object var2 with value 5.0, and one string object with the value “this is string” is assigned to the variable var3.
Example 4: Global and Local Variables: A global variable is declared in the global scope or outside of any function, which means the global variable is accessible outside or inside in any function. A local variable is declared inside any function or in the scope of any function. The local variable is only accessible in the scope of it’s declared function. If we try to access a local variable outside its function so this is an error.
# global variable g_var = "global variable" # create a function def fun1(): # declare a local variable l_var = "local variable" # print global variable print(g_var) # print local variable print(l_var) # call fun1 fun1() # print global variable again print(g_var) |
global variable local variable global variable
here the global variable print twice because we call global variable two times once in fun1 and second time outside the function.
Example 5 : Nonlocal variables : Nonlocal keyword is use to create nonlocal variables. Nonlocal variables are used in nested functions whose local scope is not defined. This means that the variable can be neither in the local nor the global scope.
# declare fun1 def fun1(): # create a local variable for fun1 var = "local" # declare fun2 def fun2(): # declare nonlocal function nonlocal var # assign value in nonlocal variable var = "nonlocal" # print inner var print("inner:", var) # call fun2 fun2() # print outer var print("outer:", var) # call fun1 for executing the program fun1() |
inner: nonlocal outer: nonlocal
Note : If we change the value of a nonlocal variable, the changes appear in the local variable.
