Python For Loops. A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string). This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages. Whenever you come up with new idea, learn or teach programming, you and others can just write and run code. Paiza.IO engine paiza.IO engine is the lightest container based code runner engine that support all(20+) popular compiler or script languages. Paiza.IO engine provides stable running time, extremely low latency without any polling,. Easy Python (Basic) Max Score: 20 Success Rate: 96.88%. Solve Challenge. List Comprehensions. Easy Python (Basic) Max Score: 10 Success Rate: 98.24%. Solve Challenge. Find the Runner-Up Score! Easy Python (Basic) Max Score: 10 Success Rate: 93.88%. Solve Challenge. Easy Python (Basic) Max Score: 10 Success Rate: 91.16%.
Python For Loops
A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).
This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages.
With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc.
Example
Print each fruit in a fruit list:
for x in fruits:
print(x)
The for loop does not require an indexing variable to set beforehand.
Looping Through a String
Even strings are iterable objects, they contain a sequence of characters:
Example
Loop through the letters in the word 'banana':
Try it Yourself »The break Statement
With the break statement we can stop the loop before it has looped through all the items:
Example
Exit the loop when x is 'banana':
for x in fruits:
print(x)
if x 'banana':
break
Example
Exit the loop when x is 'banana', but this time the break comes before the print:
for x in fruits:
if x 'banana':
break
print(x)
The continue Statement
With the continue statement we can stop the current iteration of the loop, and continue with the next:
Example
Do not print banana:
for x in fruits:
if x 'banana':
continue
print(x)
The range() Function
To loop through a set of code a specified number of times, we can use thePython Runner.py
range()
function,The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at a specified number.
Example
Using the range() function:
Try it Yourself »Note that range(6) is not the values of 0 to 6, but the values 0 to 5.
The range() function defaults to 0 as a starting value, however it is possible to specify the starting value by adding a parameter: range(2, 6), which means values from 2 to 6 (but not including 6):
Example
Using the start parameter:
Try it Yourself »The range() function defaults to increment the sequence by 1,however it is possible to specify the increment value by adding a third parameter: range(2, 30, 3):
Example
Increment the sequence with 3 (default is 1):
Try it Yourself »Python Runner Download
Else in For Loop
Python Runner File
The else keyword in afor loop specifies a block of code to be executed when the loop is finished:
Example
Print all numbers from 0 to 5, and print a message when the loop has ended:
print(x)
else:
print('Finally finished!')
Note: The else block will NOT be executed if the loop is stopped by a break statement.
Example
Break the loop when x is 3, and see what happens with the else block:
if x 3: break
print(x)
else:
print('Finally finished!')
Nested Loops
A nested loop is a loop inside a loop.
The 'inner loop' will be executed one time for each iteration of the 'outer loop':
Example
Print each adjective for every fruit:
fruits = ['apple', 'banana', 'cherry']
for x in adj:
for y in fruits:
print(x, y)
The pass Statement
for loops cannot be empty, but if you for some reason have a for loop with no content, put in the pass statement to avoid getting an error.