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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.

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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:

fruits = ['apple', 'banana', 'cherry']
for x in fruits:
print(x)
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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':

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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':

fruits = ['apple', 'banana', 'cherry']
for x in fruits:
print(x)
if x 'banana':
break
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Example

Exit the loop when x is 'banana', but this time the break comes before the print:

fruits = ['apple', 'banana', 'cherry']
for x in fruits:
if x 'banana':
break
print(x)
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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:

fruits = ['apple', 'banana', 'cherry']
for x in fruits:
if x 'banana':
continue
print(x)
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The range() Function

To loop through a set of code a specified number of times, we can use the

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range()Python Runner 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:

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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:

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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):

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Else in For Loop

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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:

for x in range(6):
print(x)
else:
print('Finally finished!')
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Note: The else block will NOT be executed if the loop is stopped by a break statement.

Example

Python

Break the loop when x is 3, and see what happens with the else block:

for x in range(6):
if x 3: break
print(x)
else:
print('Finally finished!')
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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:

adj = ['red', 'big', 'tasty']
fruits = ['apple', 'banana', 'cherry']
for x in adj:
for y in fruits:
print(x, y)
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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.

Example

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