The for loop in Python iterates over the sequence (list, tuples, dictionaries, etc.) and traverse it. For loop is beneficial for performing the iterative tasks. We can also run the same block of code multiple times by using the for loop.
This article will explain the for loop with examples.
Syntax
The for loop is declared by using the for keyword. The syntax of the for loop is as follows:
for iterator_variable in sequence:
statement(s) or body of for loop
The iterator_variable is used to iterate through the sequence. The value of the item is taken from the sequence, and the operation is performed. The for loop doesn’t terminate unless the last item in the sequence is traversed. The indentation is used to separate the body of for loop from its declaration.
Now, let’s see the examples of for loops in Python.
Examples 1: Printing the items of the list
Let’s declare a list and use the for loop to print the list items.
animal= ["cow","dog","cat","camel","lion"]
#declaring a for loop
#x is the iterator variable
for x in animal:
#printing each item of the list
print(x)
Output
Example 2: Calculating the sum of list items
Now, let’s write a program and calculate the sum of all the items of a list.
mylist=[1,2,3,4,5,6,7,8,9,10]
#declaring a variable to store sum value
sum=0
#declaring the for loop
for x in mylist:
sum=sum+x
print("The sum is: ",sum)
Output
Example 3: Traversing the string using for loop
In Python, we can also iterate the string using for loop. Let’s see an example of this.
website="linuxhint"
#declaring a for loop
for x in website:
print(x)
Output
Python for loop with else statement
Python allows us to use else statement in combination with the loops. The else statement will be executed if the loop is terminated or the list is iterated. Let’s see an example of this.
website="linuxhint"
#declaring a for loop
for x in website:
print(x)
#declaring an else statement
else:
print("Executing the else statement")
print("The end of for loop")
Output
Using break statement with the for loop
The break statement is used to control the iteration of for loop. The break statement stops the iteration of for loop after the particular iteration. It also terminates the for loop when a test condition is true. Let’s see an example of this. In the given example, the for loop is terminated when the value of the iterator is equal to the cat.
animal= ["cow","dog","cat","camel","lion"]
#declaring a for loop
#x is the iterator variable
for x in animal:
#printing each item of the list
print(x)
if (x=="cat"):
#using the break statement
break
Output
Using continue statement with the for loop
The continue statement is also used to control the iteration of for loop. The continue statement can be used to skip the current iteration, while the for loop continues from the next iteration. The continue statement skip the iteration of the for loop when a test condition is true. Let’s see an example of this.
animal= ["cow","dog","cat","camel","lion"]
#declaring a for loop
#x is the iterator variable
for x in animal:
#printing each item of the list
if (x=="cat"):
#using the continue statement
continue
print(x)
Output
In the given example, the current iteration is skipped when the value of the iterator is equal to the cat.
Using range() function in for loop
The range() function generates the numbers in sequence. We can specify the start, stop, and step size value within the range function. If the step size value is not defined, then it is 1 by default. The range() function is also used to access the indexes of the declared sequence. Let’s just take a look at the examples of the range function. We are writing the simplest program, which uses the range function to print the number 10. The range() function prints the number from 0 to 9.
for num in range(10):
#printing the value of num
print(num)
Output
Now, let’s use start, stop, and step size value with range() function.
#the start value is 1, the stop value is 30, and the step value is 3.
for num in range(1,30,3):
#printing the value of num
print(num)
Output
The range() function is also used to the get the indexes of the sequence. Let’s see an example of this where the len() function is used to return the list’s length.
animal= ["cow","dog","cat","camel","lion"]
#declaring a for loop
#x is the iterator variable
#getting the length of animal list by using the len() function
for x in range(len(animal)):
#printing each item of the list
print(animal[x])
Output
Conclusion
This article explains the use of for loop in Python with the help of simple examples. The for loop is used to iterate the container and access the items of the container. This article will be beneficial for beginners.
