Loops are an essential part of programming in Python, and they enable us to repeat a block of code for a specified number of times or until a specific condition is met. In Python, we have two types of loops: the for loop and the while loop.
The for loop is used to iterate over a sequence of elements such as a list, tuple, or string. It's a definite loop, meaning that we know the number of iterations before we start. The syntax for a for loop in Python is as follows:
for variable in sequence: # block of code to be executed
Here, variable takes the value of each element in sequence in every iteration of the loop. We can use the range() function to generate a sequence of numbers to iterate over. For example:
for i in range(10): print(i)
This will print the numbers 0 to 9, one on each line.
We can also use the for loop to iterate over elements in a list or tuple:
fruits = ['apple', 'banana', 'cherry'] for fruit in fruits: print(fruit)
This will print the elements of the fruits list, one on each line.
The while loop is used to repeat a block of code until a specific condition is met. It's an indefinite loop, meaning that we don't know the number of iterations before we start. The syntax for a while loop in Python is as follows:
while condition: # block of code to be executed
Here, condition is evaluated at the beginning of every iteration, and the loop continues until the condition is false. For example:
i = 0 while i < 10: print(i) i += 1
This will print the numbers 0 to 9, one on each line.
We can also use the while loop to repeat a block of code indefinitely:
while True: # block of code to be executed
This loop will continue indefinitely until we break out of it using a break statement.
In conclusion, loops are an essential part of programming in Python, and they enable us to repeat a block of code for a specified number of times or until a specific condition is met. The for loop is used to iterate over a sequence of elements, while the while loop is used to repeat a block of code until a specific condition is met. Understanding how to use loops is crucial for writing efficient and effective Python programs.