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