Python For loops

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What is a for loop?

A for loop is a type of loop that allows you to iterate over a sequence (such as a list, tuple, or string) or another iterable object.

The syntax of a for loop in Python is:


for item in sequence:
    # code to be executed

Here, item is a variable that takes on the value of each element in sequence on each iteration of the loop. The sequence can be any iterable object, such as a list, tuple, string, or even a range.

Using the break and continue statements

You can use the break and continue statements within a for loop to control the flow of execution.

The break statement

The break statement is used to exit a loop early. For example:


# Find the first even number in a list
numbers = [1, 3, 7, 11, 12, 15]

for number in numbers:
    if number % 2 == 0:
        print(number)
        break

Output:


12

The continue statement

The continue statement is used to skip the rest of the current iteration and move on to the next one. For example:


# Print the odd numbers in a list
numbers = [1, 2, 3, 4, 5, 6]

for number in numbers:
    if number % 2 == 0:
        continue
    print(number)

Examples of for loops

Here are some examples of for loops in Python:

Loop through a list


# Print the elements of a list
fruits = ['apple', 'banana', 'mango']

for fruit in fruits:
    print(fruit)

Output:


apple

banana

mango

Loop through a tuple


# Print the elements of a tuple
fruits = ('apple', 'banana', 'mango')

for fruit in fruits:
    print(fruit)

Output:


apple

banana

mango

Loop through a string

# Print each character of a string
string = "Hello"

for character in string:
    print(character)

output:


H
e
l
l
o

Loop through a range


# Print the numbers from 1 to 5
for i in range(1, 6):
    print(i)

Output:


1
2
3
4
5

You can also specify a step size by including the third argument in the range function:


# Print the even numbers from 1 to 10
for i in range(1, 11, 2):
    print(i)

Output:


1
3
5
7
9

Using the range function with a for loop

The range function is often used in conjunction with a for loop to repeat a block of code a certain number of times. For example:


# Print the numbers from 1 to 5
for i in range(5):
    print(i+1)

Output:


1
2
3
4
5

Looping through a list of lists

You can use a for loop to iterate over a list of lists:


# Print the elements of a list of lists
fruits = [['apple', 'banana', 'mango'], ['orange', 'strawberry', 'grape']]

for fruit_list in fruits:
    for fruit in fruit_list:
        print(fruit)

Output:


apple
banana
mango
orange
strawberry
grape

Using the enumerate function with a for loop

The enumerate function is often used with a for loop to iterate over a list and obtain the index of each element. The syntax is:


for i, item in enumerate(sequence):
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