B2. Python For Loop

In Python, a for loop is used to iterate over a sequence of elements, and execute the same block of code for each element in the sequence. The basic syntax of a for loop is as follows:

for variable in sequence:
    # code to execute for each element in the sequence

Here, variable is a variable that takes on the value of each element in the sequence during each iteration of the loop. The code block inside the loop is executed once for each element in the sequence.

The sequence can be any iterable object, such as a list, tuple, string, or dictionary.

Here’s an example of how to use a for loop in Python:

# Print each element in a list
my_list = ["apple", "banana", "orange"]

for fruit in my_list:
    print(fruit)

In this example, we’re using a for loop to print each element in the my_list list. The loop iterates through the list and assigns each element to the fruit variable. The print function is then called with the fruit variable as the argument, which prints each element in the list to the console.

The output of this code would be:

apple
banana
orange

Note that the for loop automatically stops iterating when it reaches the end of the sequence.

Python loop over a list :

In the below example we check on how to use a for loop to iterate over a list in Python:

# Iterate over a list and print each element
my_list = [1, 2, 3, 4, 5]

for element in my_list:
    print(element)

In this example, we’re creating a list called my_list with the elements 1, 2, 3, 4, and 5. We then use a for loop to iterate over each element in the list and print it to the console using the print function.

The output of this code would be:

Note that the for loop automatically stops iterating when it reaches the end of the list. You can perform any operations you like on each element of the list inside the loop, such as adding them together, checking if they meet a certain condition, or appending them to a new list.

Python loop with range() :

In Python, the built-in range() function can be used in conjunction with a for loop to repeat a code block a specified number of times. The range() function generates a sequence of numbers that can be used to control the number of iterations in a for loop.

The basic syntax of a for loop with range() is as follows:

for variable in range(start, stop, step):
    # code to execute for each value of the variable

Here, start is the starting value of the sequence (default is 0), stop is the exclusive ending value of the sequence, and step is the increment between values in the sequence (default is 1).

The variable takes on each value in the sequence during each iteration of the loop, and the code block inside the loop is executed once for each value.

Here’s an example of how to use a for loop with range() in Python:

# Print the numbers from 0 to 4
for i in range(5):
    print(i)

In this example, we’re using a for loop with range() to print the numbers from 0 to 4.

The range(5) function generates a sequence of numbers from 0 to 4 (inclusive), and the for loop iterates over each value in the sequence and assigns it to the i variable.

The print function is then called with the i variable as the argument, which prints each number to the console.

The output of this code would be:

Note that the for loop automatically stops iterating when it reaches the end of the sequence generated by the range() function.

Python for loop with else :

In Python, it is possible to use an else statement in conjunction with a for loop. The else block will be executed after the loop has completed, but only if the loop did not encounter a break statement.

The basic syntax of a for loop with else is as follows:

for variable in sequence:
    # code to execute for each element in the sequence
else:
    # code to execute if the loop completed without encountering a break statement

The else block is optional, and is executed after the loop has completed, but only if the loop did not encounter a break statement.

Here’s an example of how to use a for loop with else in Python:

# Check if a number is prime
num = 7

for i in range(2, num):
    if num % i == 0:
        print("The number is not prime.")
        break
else:
    print("The number is prime.")

In this example, we’re using a for loop with range() to check if the value of num is prime. The loop iterates over each integer from 2 to num - 1, and checks if num is divisible by that integer.

If num is divisible by any integer, the loop prints “The number is not prime” and exits using a break statement.

If the loop completes without encountering a break statement, then num is prime and the else block is executed, which prints “The number is prime.” In this case, since num is 7, which is a prime number, the output will be “The number is prime.”

B2. Python For Loop

Python loop over a list : #

Python loop with range() : #

Python for loop with else : #

Python loop over a list :

Python loop with range() :

Python for loop with else :