Difference between for loop and while loop in Python
Python is considered a very popular programming language that has been developed with a dynamic semantics ability. It enables developers to write concise code while improving readability. Generally, loops are used in programming to execute the statements more than once, and these statements are executed based on the condition provided or until the condition is true. In Python, the loop statements mainly include two different loops, namely the for loop and the while loop. Both loops have their own characteristics and are used based on requirements. In this article, we will discuss the difference between for loop and while loop in Python.
For Loop
This loop statement is mainly used for repeated execution of blocks of code iteratively on the elements of a sequence like a list, tuple, string, etc. The sequence of elements in for loop is iterated and the code block that follows the ‘for’ statement is executed once for each item in the sequence.
Example:
fruits = ['apple', 'banana', 'orange']
for fruit in fruits:
print("I am eating", fruit)
Output:
I am eating apple
I am eating banana
I am eating orange
In the above example, the for
loop iterates through the elements of the fruits
list and print()
statement is executed for each item in the list.
While Loop
This loop statement is mainly used for repeated execution of a block of code as long as the condition given in the while statement evaluates to True. The code block will keep executing until the condition provided in the while statement is true.
Example:
count = 0
while count < 3:
print("Run this code")
count += 1
Output:
Run this code
Run this code
Run this code
In the above example, the while
loop repeatedly executes the print()
statement until the count
variable reaches the condition of 3.
Key Differences between for loop and while loop
- Structure: The structure used in the
for
loop is such that it iterates over a sequence or range, while thewhile
loop is used for the repetition of a sequence of code based on the condition being satisfied. - Implementation: The
for
loop is used when the total number of iterations is already known, where it is necessary to iterate through a sequence or range. On the other hand, while loops are used when the number of iterations is not known, and it waits for the condition to become false to terminate the loop, which makes it more flexible thanfor
loops. - Use Case:
for
loops are best suited for iterating through a known sequence, such as iterative solutions or processing lists, because these loops are predictable and easy to control.while
loops are ideal when you are waiting for specific status changes or continuous inputs to terminate the loop, such as using the loop to control user input, compute iterations, or migrate data that is still being processed.
Conclusion
In conclusion, both loops – the for
loop and the while
loop – provide similar functionality of executing a block of code repeatedly. The critical difference between the two lies in their syntax and use case. The for
loop is best for iterating over a fixed range or sequence while the while
loop is ideal to continue executing code as long as the condition is true. As a Python developer, it is essential to understand the differences between these two loops and choose the most suitable one based on specific use cases to optimize code performance.