For loop vs while loop in Python
| Different basis for comparison | For loop | While loop |
| Declaration | for value in range: <statement> | while condition: <statement> |
| Use loop | The for loop is used only when we alread ... | The while loop is used when we did not k ... |
| Condition | If there is no condition then the loop i ... | But in the case of while if the conditio ... |
| Iteration | In the loop statement, it is always writ ... | But in the case of while we can store st ... |
Full Answer
What is the difference between for loop and while loop?
While condition
- The initialization and the condition checking is done at the beginning of the loop.
- It is used only when the number of iterations isn’t known.
- If the condition is not mentioned in the 'while' loop, it results in a compilation error.
Why there is no DO WHILE loop in Python?
As there is no proper indentation for specifying do while loop in python, therefore there is no do-while loop in python, but it is done with while loop itself. The body of the while loop starts with indentation, and as soon as the unindented line is found, then that is marked as the end of the loop. Conclusion – Do While Loop in Python
Do while vs for loop?
Just use whichever loop seems more appropriate to the task at hand. In general, you should use a for loop when you know how many times the loop should run. If you want the loop to break based on a condition other than the number of times it runs, you should use a while loop.
How to exit a while loop in Python?
break is a reserved keyword in Python. If typing it in a Python IDLE, you will see that it turns orange, indicating that it is a special reserved word in Python. So this is how you can exit a while loop in Python using a break statement.
What is difference between for and while loop in Python?
The for statement iterates through a collection or iterable object or generator function. The while statement simply loops until a condition is False.
Can we use and in while loop in Python?
Summary. The else block can be used with both the for and while loop. It is always executed. The break keyword is used to terminate the execution.
Can you have two while loops Python?
Python While Loop Multiple Conditions. To combine two conditional expressions into one while loop, you'll need to use logical operators. This tells Python how you want all of your conditional expressions to be evaluated as a whole.
Can you put a for loop in a while loop Python?
You can put a for loop inside a while, or a while inside a for, or a for inside a for, or a while inside a while. Or you can put a loop inside a loop inside a loop. You can go as far as you want.
How do you write a for loop with two conditions?
Note: both are separated by comma (,). 2. It has two test conditions joined together using AND (&&) logical operator. Note: You cannot use multiple test conditions separated by comma, you must use logical operator such as && or || to join conditions.
What is the difference between for and while loop?
The 'for' loop used only when we already knew the number of iterations. The 'while' loop used only when the number of iteration are not exactly known. If the condition is not put up in 'for' loop, then loop iterates infinite times. If the condition is not put up in 'while' loop, it provides compilation error.
What are the 3 types of loops in Python?
Loop Typeswhile loop.for loop.nested loops.
How do you write multiple loops in Python?
First, Write an outer for loop that will iterate the first list like [for i in first] Next, Write an inner loop that will iterate the second list after the outer loop like [for i in first for j in second] Last, calculate the addition of the outer number and inner number like [i+j for i in first for j in second]
Why you would use a for loop versus a while loop?
In general, you should use a for loop when you know how many times the loop should run. If you want the loop to break based on a condition other than the number of times it runs, you should use a while loop.
Can I combine for and while loop?
To answer your question, yes, the while loop will terminate when i is greater than or equal to 9000, but only if while knows that this is the case.
Can you use a for and while loop together?
Use a for loop when you know the loop should execute n times. Use a while loop for reading a file into a variable. Use a while loop when asking for user input. Use a while loop when the increment value is nonstandard.
How do you convert a for loop to a while loop?
To convert a for loop to while loop we need to simply add the initialization statement before the while loop./* For loop */ int i; for(i = 0; i < 10; i++) { } ... /* While loop */ while(*str++ != NULL) { length++; ... /* Do while loop */ do. { status = check_connection(); ... /* For loop */ int i; for(i = 0; i < 10; i++) {
What is a while loop in Python?
In other words, we need a loop, and the most simple looping mechanism in Python is the while loop. A while loop runs as long as a certain condition is True.
Why are loops important in Python?
When programming in Python or other programming languages, loops are very important to understand in order to create dynamic programs that can do many different things. Loops are a programming construct that repeats a section of code a set number of times until the desired result is achieved. Much of the power of programming is having ...
What is iterable in Python?
Lists such as trees are one of Python’s iterable objects. Strings, tuples, dictionaries, sets, and some other elements are also iterable objects. When we iterate over a list or tuple, we access one item at a time. With String iteration, you are accessing one character at a time.
What is the purpose of continue in a loop?
You can use the continue keyword to return to the start of a loop based on the result of a conditional test. When a program reaches a continue statement, the program jumps right back to the start of the loop and reevaluates the condition of the loop. For example, consider a loop that counts from 1 to 10 but prints only the even numbers:
What is the other clause in a for loop?
Just like the while loop, for has an optional else clause that you can use to check if the for loop completed normally. If a break was not called, the else statement is run. This can be useful when you want to check that the previous for loop ran to completion, instead of being stopped early with a break. The for loop in the following example prints each letter of the string ‘Programming’ while looking for the letter ‘Z’. Since it is never found, the break statement is never hit and the else clause is run.
How to break out of a while loop?
You can break out of a while loop with the break keyword. This is used when you want a semi-infinite loop. In other words, you want to keep looping until something specific happens, but you’re not sure when that might happen. What is a good example of this? How about a program that lets you type in a word, and the program will print the string in reverse. The program will continue in an infinite loop until you type the ‘q’ character to quit, which will break the loop. This is an example of using if statements inside a while loop.
Why is the highlighted line important in a while loop?
The highlighted line is super important in a while loop. It is used to increment the value of the count variable.
What happens when a loop is a while loop?
In a while loop, the condition is first checked. If it is true , the code in loop body is executed. This process will repeat until the condition becomes false.
What is a for loop?
A for loop is a type of loop that runs for a preset number of times. It also has the ability to iterate over the items of any sequence, such as a list or a string.
What is the difference between continue and break?
The difference between continue and break is that the break keyword will “jump out” of the loop, but continue will “jump over” one cycle of the loop
What is a loop in programming?
Loops are an essential construct in all programming languages. In a loop structure, the program first checks for a condition. If this condition is true, some piece of code is run. This code will keep on running unless the condition becomes invalid.
How many kinds of loops are there in Python?
In Python, there are two kinds of loop structures:
What does the while statement do?
Our while statement first checks whether n is less than the length variable. Since this is true, the program will print out the items in the numbers list. In the end, we are incrementing the n variable
Why use pass in Python?
Use the pass statement if you don’t want any command to run. In other words, pass allows you to perform a “null” operation. This can be crucial in places where your code will go but has not been written yet.
What is a loop in Python?
A loop is a programming structure that repeats a set of instructions until a condition is met. You can use loops to for example iterate over a list of values, accumulate sums, repeat actions, and so on. In Python, you can use for and while loops to loop through sequences.
When to use "other" in a for loop?
You can use an else statement in a for loop. The else block is executed when the looping comes to an end
What is list comprehension in Python?
List comprehension is a built-in feature in Python. You can replace for loops with one-liner expressions.
How to loop numbers from a starting number to infinity?
You can use itertools.count () method to loop numbers from a starting number to infinity.
What is a lambda function?
A lambda function is a function without a name. It takes any number of arguments and only has one expression. To demonstrate, here is a lambda function that squares a number:
How to control the flow of a loop?
You can control the flow of the execution of a loop using break and continue statements. These work the same way for both while loop and for loops.
What does the continue statement do?
The continue statement skips the “rest of the loop” and begins the next iteration.
What is a while loop?
The while loop statement is used to repeat a block of code till a condition is fulfilled. When we don’t know the exact number of times, a loop statement has to be executed. We make use of while loops. This way, till the test expression holds true, the loop body will be executed.
When to use while loops?
We use while loops when we don’t know the number of times we want to loop over a code, but we know the condition which determines the execution of the loop body . Whereas for loops are particularly used to iterate over a sequence. When you know the number of times the loop has to be executed, then using a range function in for loop, we can achieve that.
What is a for loop in Python?
The for loop in python is used to iterate over a given sequence. The sequence can be a string, a list, a tuple, a set, a dictionary, etc. As long as the length of the sequence is not reached, it will iterate over that sequence. The for loop contains initialization, the test expression, and the increment/decrement expression in the C language. Whereas in the case of python, we only have to mention the value and the sequence to be iterated.
What is condition in Python?
The ‘condition’ will be the criteria based on which the loop body will be executed. Till the condition holds true, the loop body is executed. As soon as it becomes false, python will stop executing the loop body.
What is the condition to be fulfilled in a while loop?
Inside the while loop, the condition to be fulfilled is that the value of ‘n’ should always be greater than zero. Inside the loop, we add the value of ‘n’ to ‘sum’ and then decrement ‘n’. While the value of ‘n’ will become zero, the while loop will stop executing and then print the ‘sum’ variable.
Why do we have two different loop statements in Python?
They have the same functionality – i.e., they will execute a certain piece of code only if a condition is met. Yet, they differ in syntax and some other aspects.
Which is faster, for loop with range or while loop with increment?
As a result, using dissassembly, you can clearly observe that for loop with range () function is clearly faster than the while loop with increment method.
What is a loop exercise in Python?
Python Loop Exercises: For loop () and while loop () is used to iterate over each element or data depending upon the condition satisfied. While on the other side to control the flow of a program, we have control flow statements i.e. if, if-else statements in Python.
Do loops and control flow statements work together?
In most cases,we use loop s and control flow statements together in our program. Looping and control flow statements are the backbone of any programming language. So, it is necessary to have a good understanding and command over these concepts.
When can we run a block of code with the else statement?
With the else statement we can run a block of code once when the condition no longer is true:
Can you stop a loop with break statement?
With the break statement we can stop the loop even if the while condition is true: