54 lines
1.9 KiB
Markdown
54 lines
1.9 KiB
Markdown
---
|
|
title: While Loop Statements
|
|
---
|
|
## While Loop Statements
|
|
|
|
<!-- Please add any articles you think might be helpful to read before writing the article -->
|
|
|
|
Python utilizes the `while` loop similarly to other popular languages. The `while` loop evaluates a condition then executes a block of code if the condition is true. The block of code executes repeatedly until the condition becomes false.
|
|
|
|
The basic syntax is:
|
|
|
|
```python
|
|
counter = 0
|
|
while counter < 10:
|
|
# Execute the block of code here as
|
|
# long as counter is less than 10
|
|
```
|
|
|
|
An example is shown below:
|
|
```python
|
|
days = 0
|
|
week = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday']
|
|
while days < 7:
|
|
print("Today is " + week[days])
|
|
days += 1
|
|
```
|
|
|
|
Output:
|
|
|
|
```
|
|
Today is Monday
|
|
Today is Tuesday
|
|
Today is Wednesday
|
|
Today is Thursday
|
|
Today is Friday
|
|
Today is Saturday
|
|
Today is Sunday
|
|
```
|
|
Line-by-Line Explanation of the above CODE:
|
|
1. the variable 'days' is set to a value 0.
|
|
2. a variable week is assigned to a list containing all the days of the week.
|
|
3. while loop starts
|
|
4. the block of code will be executed until the condition returns 'true'.
|
|
5. the condition is 'days<7' which rougly says run the while loop till the point the variable days is less than 7
|
|
6. So when the days=7 the while loop stops executing.
|
|
7. the days variable gets updated on every iteration.
|
|
8. When the while loop runs for the first time the line 'Today is Monday' is printed onto the console and the variable days becomes equal to 1.
|
|
9. Since the variable days is equal to 1 which is less than 7 so the while loop is executed again.
|
|
10. It goes on again and again and when the console prints 'Today is Sunday' the variable days is now equal to 7 and the while loop stops executing.
|
|
|
|
#### More Information:
|
|
|
|
- <a href='https://docs.python.org/3/reference/compound_stmts.html#the-while-statement' target='_blank' rel='nofollow'>Python `while` statement documentation</a>
|