- For loop permit us to iterate over a sequence of values.
let’s examine below example;
for x in range (5):
- For loops starts with the keyword for with a colon at the top of the road .
- When we look like in function definitions,while loops and if statements, the body of the for loop begins on subsequent line and is indented to the proper .
- But what about those things in between the for keyword and therefore the colon?
- In our example, we’re using the range() function to make a sequence of numbers that our for loop can iterate over.
- During the case like this,our variable x points to the present element within the sequence because the for loop iterates over the sequence of numbers.Keep in mind that in Python and numerous programming languages, a variety of numbers will start at 0,and the list of numbers generated are going to be one but the provided value.
- So range(5) will create a sequence of numbers from 0 to 4,for total of 5 numbers.
- When we bring altogether, the range(5) function will create a sequence of numbers from 1 to 4.Our for loop will iterate over this sequence of numbers,one at at time,making the numbers accessible through the variable x and therefore the code within our loop body will execute for every iteration through the sequence.
- So for the initial loop, x shall contain 0.the next loop,1,and so on until it reaches 4.Once the top of the sequence comes up, the loop will exit and therefore the code will continue.
- The facility of for loops comes from the very fact that it can iterate over a sequence of any quite data,not just a variety of numbers.We may describe for loops to iterate over an inventory repeatedly for strings,such as usernames or lines during a file.
- This is not sure whether to use a for loop or a short time loop? Always keep in mind that a short time loop is great for performing an action over and over until a condition has changed.A for loop works well once you want to iterate over a sequence of elements.
Infinite loops and code Blocks
- Another easy mistake that can happen when using loops in introducing an infinite loop.
- An infinite loop is that in which the code block in the loop will continue to execute and never stop.
- This may happen when the condition being evaluated in a while loop doesn’t change.
- Pay close attention to your variables and what possible values they can take. Think about unexpected values,like zero.