- Python while loop is used to repeat a block of code until the specified condition is False.
- The while loop is used when we don’t know the number of times the code block has to execute.
- We should take proper care in writing while loop condition if the condition never returns False, the while loop will go into the infinite loop.
- Every object in Python has a boolean value. If the value is 0 or None, then the boolean value is False. Otherwise, the boolean value is True.
- We can define an object boolean value by implementing __bool__ () function.
- We use the reserved keyword – while – to implement the while loop in Python.
- We can terminate the while loop using the break statement.
- We can use continue statement inside while loop to skip the code block execution.
- Python supports nested while loops.
Full Answer
How do you use a while loop in Python?
Use while true with if statement and break statement to create While loop yes or no in Python. Simple if while condition equal to “N” then wait for the user input of Y before exiting. Example While loop yes or no in Python Simple example code using 2 while loops. If the user inputs the Read More...
How to write a while loop Python?
While Loop. In Python, while loops are constructed like so: while [a condition is True]: [do something] The something that is being done will continue to be executed until the condition that is being assessed is no longer true. Let’s create a small program that executes a while loop. In this program, we’ll ask for the user to input a password.
What does while loop mean in Python?
- The while loop evaluates the test expression inside the parenthesis () .
- If the test expression is true, statements inside the body of while loop are executed.
- The process goes on until the test expression is evaluated to false.
- If the test expression is false, the loop terminates (ends).
How to use Python while loop user input with examples?
Using a while Loop with Lists and Dicitonaries
- Moving Items from One List to Another. Consider a list of newly registered but unverified users of a website. ...
- Removing All Instances of Specific Values from a List. In previous notes ( located here) we used remove () to remove a specific value from a list. ...
- Filling a Dictionary with User Input. ...
What is the use of while loop in Python?
The while loop in Python is used to iterate over a block of code as long as the test expression (condition) is true. We generally use this loop when we don't know the number of times to iterate beforehand.
How do you use the while loop?
A "While" Loop is used to repeat a specific block of code an unknown number of times, until a condition is met. For example, if we want to ask a user for a number between 1 and 10, we don't know how many times the user may enter a larger number, so we keep asking "while the number is not between 1 and 10".
Do And while loop in Python?
The do while Python loop executes a block of code repeatedly while a boolean condition remains true. The Python syntax for while loops is while[condition]. A “do while” loop is called a while loop in Python. Most programming languages include a useful feature to help you automate repetitive tasks.
What is the use of while and do while loop?
While loop checks the condition first and then executes the statement(s), whereas do while loop will execute the statement(s) at least once, then the condition is checked.
What is while loop syntax?
The Do While Loop This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true.
How does while true work in Python?
The "while true" loop in python runs without any conditions until the break statement executes inside the loop. To run a statement if a python while loop fails, the programmer can implement a python "while" with else loop. Python does not support the "do while" loop.
How do you repeat a while loop in Python?
0:1810:12A while loop starts with the keyword. While followed by a test condition followed by a colon. ThenMoreA while loop starts with the keyword. While followed by a test condition followed by a colon. Then we write the body of the loop in the next lines. Notice the spaces before the body of the loop.
Why do-while loop is not used in Python?
There is no do... while loop because there is no nice way to define one that fits in the statement: indented block pattern used by every other Python compound statement. As such proposals to add such syntax have never reached agreement.
How does a while loop start?
Syntax. The while loop starts by evaluating condition . If condition evaluates to true , the code in the code block gets executed. If condition evaluates to false , the code in the code block is not executed and the loop ends.
Do-while loop is useful when we want?
A do - while loop is useful when we want that the statements within the loop must be executed.
Which is faster while or do while?
do-while is fastest to run the first iteration as there is no checking of a condition at the start.
What is the key point of a while loop?
Here, key point of the while loop is that the loop might not ever run. When the condition is tested and the result is false, the loop body will be skipped and the first statement after the while loop will be executed.
What is an infinite loop?
The Infinite Loop. A loop becomes infinite loop if a condition never becomes FALSE. You must use caution when using while loops because of the possibility that this condition never resolves to a FALSE value. This results in a loop that never ends. Such a loop is called an infinite loop.
What is indentation in Python?
In Python, all the statements indented by the same number of character spaces after a programming construct are considered to be part of a single block of code. Python uses indentation as its method of grouping statements.
What is a while loop in Python?
In Python, While Loops is used to execute a block of statements repeatedly until a given condition is satisfied. And when the condition becomes false, the line immediately after the loop in the program is executed. While loop falls under the category of indefinite iteration. Indefinite iteration means that the number of times ...
When is the else clause executed in Python?
The else clause is only executed when your while condition becomes false. If you break out of the loop, or if an exception is raised, it won’t be executed. Note: The else block just after for/while is executed only when the loop is NOT terminated by a break statement. # Python program to demonstrate. # while-else loop.
What is indentation in Python?
Python uses indentation as its method of grouping statements. When a while loop is executed, expr is first evaluated in a Boolean context and if it is true, the loop body is executed. Then the expr is checked again, if it is still true then the body is executed again and this continues until the expression becomes false.
What happens when a loop control statement leaves a scope?
Loop control statements change execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed. Python supports the following control statements.
Can a while block be separated by semicolons?
If there are multiple statements in the block that makes up the loop body , they can be separated by semicolons (;).
While loop in python
In python, while loop is used iterate over the code until the given condition gets false.
Infinite while loop in python
In python, Infinite while loop is the loop where the while condition never gets false and the loop will never end.
Break statement in python
In python, break statement is used to stop the while loop even if the condition is true.
Continue statement in python
In python, the continue statement is used to stop the current iteration, and then it will continue with the next till the last.
Python while loop multiple conditions
In python, the while loop multiple conditions are used when two simple boolean conditions are joined by the logical operator ” and “.
Python while loop with else statement
In python, the else part is associated with while loop statements. The else part is executed when the condition becomes false.
Reverse using while loop python
Python while loop is used to repeatedly execute some statements until the condition is true. To get the element in the reverse order we will use while loop which will iterate till the first element and keep on decrementing “r”.
What is a do while loop?
The general syntax of a do while loop in other programming languages looks something like this:
How to emulate a do while loop in Python
To create a do while loop in Python, you need to modify the while loop a bit in order to get similar behavior to a do while loop in other languages.