For Loop Statements

Similar to while loop, for loops are also used to execute the same instruction again and again until the conditions get satisfied and also helps to iterating list sequence, tuple sequence etc.

For Loop

There are two use cases available for FOR loop statement in python

First Use Case - Iterating over the sequence data types without any specific index variable

#For Loop - Without Index
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for each_month in month_list:
    print(each_month)

Output

Jan
Feb
Mar
Apr
May

Second Use Case - Iterating with specified number of times - Using Range Function

#For Loop - With Index
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    print(month_list[index])

Output

Jan
Feb
Mar
Apr
May

For Break

Even though the condition is true still we can stop the loop with the help of break statement

#For Break
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    if month_list[index]=="Apr":
        break
    print(month_list[index])

Output

Jan
Feb
Mar

For Continue

Even though the condition is true still we can stop the specific iteration using continue statement

#For Continue
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    #only skip April month
    if month_list[index]=="Apr":
        continue
    print(month_list[index])

Output

Jan
Feb
Mar
May

For Else

One of the unique feature in python is for loop with else clause. When the condition get false it will execute the else statement

#For Else
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    print(month_list[index])
else:
    print("I am else block")

Output

Jan
Feb
Mar
Apr
May
I am else block

For Break Else

When break is executed, the else wont execute in for loop

#For Break Else
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    print(month_list[index])
    if month_list[index]=="Mar":
        break
#Else block wont execute since it breaks
else:
    print("I am else block")

Output

Jan
Feb
Mar

For Continue Else

Else statement execute for continue since it will only skip only the particular execution

#For Continue Else
month_list = ["Jan", "Feb", "Mar", "Apr", "May"]

for index in range(0, len(month_list)):
    if month_list[index]=="Mar":
        continue
    print(month_list[index])
#Else block execute since it continues
else:
    print("I am else block")

Output

Jan
Feb
Apr
May
I am else block