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Python For Loop

For loop in Python is used to iterate over the sequence of elements. The sequence can be a list, tuple or a string. We can also use loop to execute statements repeatedly.


Python for loop Syntax

for element in sequence:
    statement-1
    ...
    statement-n

Python for loop is slightly different than other programming language because it does not require to set indexing variable.

Python for loop Example

Let’s understand the working of for loop by a simple example.

list1 = [1,5,6,8,5]
for element in list1
    print(element)
Output:
1
5
6
8
5

Explaination

Notice, it is so easy to use for loop and iterate over the list. No need to initialize and increment variable as we do in other programming languages.


Python for loop using range function

Range is a built-in function that returns an object of a sequence. It can be applied to for loop for iterating over the elements of the sequence. It is beneficial when we want to iterate over the integer values.

Python for loop Example

# Creating a range
r = range(1,5,1)
# for loop
for elemnt in r:
    print(elemnt)
Output:
1
2
3
4

In this example, we created a range that starts from 1 and goes to 4. the last number is excluded, so the loop iterates till 4.


Python for loop with break statement

The break statement is used to terminate the loop execution. In for loop, we can use break to stop execution at certain condition. If you are using nested loop, only inner loop terminates.

Example

# Creating a range
r = range(1,5,1)
# for loop
for elemnt in r:
    if elemnt == 4:
        break
    print(elemnt)
Output:
1
2
3

In the above example, loop iterates and when it encounter element 4, it breaks the loop and stops further execution.


Python for loop using continue Statement

continue is a keyword in python which is used to skip the current executing iteration and resume the execution from next iteration. It is mostly used in loops to manage loop’s execution flow.

Example

# Creating a range
r = range(1,5,1)
# for loop
for elemnt in r:
    if elemnt == 3:
        continue
    print(elemnt)
Output:
1
2
4

In this example, when loop reaches to third iteration, then it skips current iteration and start from the next iteration.


Python for using else Statement

Python allows to use else statement with for loop. The else block executes when the for loop is completed.

Example

s1 = "java"
for value in s1:
    print(value)
else:
    print("for loop completed")
Output:
j
a
v
a
for loop completed

You can see, in this example, when the for loop finished, else block executed.


Python Nested For Loop

Loop inside another loop forms a nested loop. We can have any number of loop inside the loop as per the program logic requirement but it is recommended not to use more nested loop because it makes program complex and difficult to debug.

Example

list1 = ["Python", "Java", "C"]
list2 = ["is a Programming language"]
for l1 in list1:
    for l2 in list2:
        print(l1, l2)
Output:
Python is a Programming language
Java is a Programming language
C is a Programming language