{"id":39,"date":"2024-01-24T13:58:38","date_gmt":"2024-01-24T13:58:38","guid":{"rendered":"https:\/\/learnpython.elegantwallp.com\/?p=39"},"modified":"2024-01-24T13:58:40","modified_gmt":"2024-01-24T13:58:40","slug":"python-for-loop-with-range","status":"publish","type":"post","link":"https:\/\/learnpython.elegantwallp.com\/2024\/01\/24\/python-for-loop-with-range\/","title":{"rendered":"Python for Loop with Range"},"content":{"rendered":"\n

Summary<\/strong>: in this tutorial, you\u2019ll learn about the Python for<\/code> loop and how to use it to execute a code block a fixed number of times.<\/p>\n\n\n\n

Introduction to Python for loop statement with the range() function<\/h2>\n\n\n\n

In programming, you often want to execute a block of code multiple times. To do so, you use a for<\/code> loop.<\/p>\n\n\n\n

The following illustrates the syntax of a for<\/code> loop:for index in range(n): statement<\/code>Code language: Python (python)<\/small><\/p>\n\n\n\n

In this syntax, the index<\/code> is called a loop counter<\/strong>. And n<\/code> is the number of times that the loop will execute the statement<\/code>.<\/p>\n\n\n\n

The name of the loop counter doesn\u2019t have to be index<\/code>, you can use whatever name you want.<\/p>\n\n\n\n

The range()<\/code> is a built-in function in Python. It\u2019s like the print()<\/code> function in the sense that it\u2019s always available in the program.<\/p>\n\n\n\n

The range(n)<\/code> generates a sequence of n<\/code> integers starting at zero. It increases the value by one until it reaches n<\/code>.<\/p>\n\n\n\n

So the range(n)<\/code> generates a sequence of numbers: 0<\/code>,1<\/code>, 2<\/code>, \u2026n-1<\/code>. Note that it\u2019s always short of the final number (n<\/code>).<\/p>\n\n\n\n

The following diagram illustrates the for<\/code> loop statement:<\/p>\n\n\n\n

\"Python<\/figure>\n\n\n\n

The following example shows how to use the for<\/code> loop with the range()<\/code> function to display 5 numbers from 0 to 4 to the screen:<\/p>\n\n\n\n

for index in range(5): print(index)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
0 1 2 3 4<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this example, the for<\/code> loop executes the statement print(index)<\/code> exactly five times.<\/p>\n\n\n\n
If you want to show 5 numbers from 1 to 5 on the screen, you can do something like this:<\/p>\n\n\n\n
for index in range(5): print(index + 1)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
1 2 3 4 5<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this example, we increase the index<\/code> by one in each iteration and print it out. However, there\u2019s a better way to do it.<\/p>\n\n\n\n
Specifying the starting value for the sequence<\/h3>\n\n\n\n
By default, the range()<\/code> function uses zero as the starting number for the sequence.<\/p>\n\n\n\n
In addition, the\u00a0range()<\/code>\u00a0function allows you to specify the starting number like this:<\/p>\n\n\n\n
range(start, stop)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this syntax, the range()<\/code> function increases the start<\/code> value by one until it reaches the stop<\/code> value.<\/p>\n\n\n\n
The following example uses a\u00a0for<\/code>\u00a0loop to show five numbers, from 1 to 5 to the screen:<\/p>\n\n\n\n
for index in range(1, 6): print(index)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
1 2 3 4 5<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Specifying the increment for the sequence<\/h3>\n\n\n\n
By default, the range(start, stop)<\/code> increases the start<\/code> value by one in each loop iteration.<\/p>\n\n\n\n
To increase the\u00a0start<\/code>\u00a0value by a different number, you use the following form of the\u00a0range()<\/code>\u00a0function:<\/p>\n\n\n\n
range(start, stop, step)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
In this form, you can specify the value that the range()<\/code> function should increase.<\/p>\n\n\n\n
The following example shows all the odd numbers from 0 to 10:<\/p>\n\n\n\n
for index in range(0, 11, 2): print(index)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
0 2 4 6 8 10<\/code><\/code><\/pre>\n\n\n\n
Using Python for loop to calculate the sum of a sequence<\/h2>\n\n\n\n
The following example uses the for loop statement to calculate the sum of numbers from 1 to 100:<\/p>\n\n\n\n
sum = 0 for num in range(101): sum += num print(sum)<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
Output:<\/p>\n\n\n\n
5050<\/code>Code language: Python (python)<\/small><\/code><\/pre>\n\n\n\n
How it works.<\/p>\n\n\n\n
    \n
  • First, the sum is initialized to zero.<\/li>\n\n\n\n
  • Second, the sum is added with the number from 1 to 100 in each iteration.<\/li>\n\n\n\n
  • Finally, show the sum to the screen.<\/li>\n<\/ul>\n\n\n\n
    By the way, if you\u2019re a mathematician, you can use the simple formula:<\/p>\n\n\n\n
    n = 100 sum = n * (n+1)\/2 print(sum)<\/code><\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
    Summary: in this tutorial, you\u2019ll learn about the Python for loop and how to use it to execute a code block a fixed number of times. Introduction to Python for loop statement with the range() function In programming, you often want to execute a block of code multiple times. To do so, you use a for loop. The following […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"class_list":["post-39","post","type-post","status-publish","format-standard","hentry","category-3-control-flow"],"_links":{"self":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/39","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/comments?post=39"}],"version-history":[{"count":1,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/39\/revisions"}],"predecessor-version":[{"id":40,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/posts\/39\/revisions\/40"}],"wp:attachment":[{"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/media?parent=39"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/categories?post=39"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/learnpython.elegantwallp.com\/wp-json\/wp\/v2\/tags?post=39"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}