Difference between revisions of "For loop in Python"

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Example
 
  
Print each fruit in a fruit list:
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=loop through items or a string=
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==Example: Print each fruit in a fruit list:==
  
 
'''The for loop does not require an indexing variable to set beforehand.'''
 
'''The for loop does not require an indexing variable to set beforehand.'''
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</syntaxhighlight>
 
</syntaxhighlight>
  
Looping Through a String
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==Example: Looping Through a String==
  
 
Even strings are iterable objects, they contain a sequence of characters:
 
Even strings are iterable objects, they contain a sequence of characters:
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</syntaxhighlight>
 
</syntaxhighlight>
  
 +
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=loop through a set of number=
  
 
'''The range() Function'''
 
'''The range() Function'''
 
 
To loop through a set of code a specified number of times, we can use the range() function,
 
To loop through a set of code a specified number of times, we can use the 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.
 
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
+
==Example: Using the range() function:==
 
 
Using the range() function:
 
 
<syntaxhighlight lang="Python">
 
<syntaxhighlight lang="Python">
 
for x in range(6):
 
for x in range(6):
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  however it is possible to specify the increment value by adding a third parameter: range(2, 30, 3):
 
  however it is possible to specify the increment value by adding a third parameter: range(2, 30, 3):
  
Example
+
==Example: Increment the sequence with 3 (default is 1):==
  
Increment the sequence with 3 (default is 1):
 
 
<syntaxhighlight lang="Python">
 
<syntaxhighlight lang="Python">
 
for x in range(2, 30, 3):
 
for x in range(2, 30, 3):
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-----advance stuff-----
 
  
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=advanced stuff=
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 +
=-Nested Loops==
  
Nested Loops
 
 
A nested loop is a loop inside a loop.
 
A nested loop is a loop inside a loop.
  

Revision as of 14:37, 28 August 2024

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.


loop through items or a string

Example: Print each fruit in a fruit list:

The for loop does not require an indexing variable to set beforehand.

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

Example: Looping Through a String

Even strings are iterable objects, they contain a sequence of characters:

for x in "banana":
  print(x)


loop through a set of number

The range() Function To loop through a set of code a specified number of times, we can use the 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:

for x in range(6):
  print(x)
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):


for x in range(2, 6):
  print(x)


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):

for x in range(2, 30, 3):
  print(x)



advanced stuff

-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)

source: https://www.w3schools.com/python/python_for_loops.asp