Python For Loops

Python For Loops

A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string).

This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages.

With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc.

Example:

Note:  The for loop does not require an indexing variable to set beforehand.

The range() function

• It is type of iterator
• Creates a list containing arithematic progression

Syntax:

range(stop)
range(start, stop)
range(start, stop, step)

Note: Loops will stop one position before the stop value

Note: Step is the amount of increments per iteration

Example:

String Traversal 

Even strings are iterable objects, they contain a sequence of characters.

Example:

The break Statement

With the break statement we can stop the loop before it has looped through all the items.

Example:

The continue Statement

With the continue statement we can stop the current iteration of the loop, and continue with the next.

Example:

Nested Loops

A nested loop is a loop inside a loop.

The "inner loop" will be executed one time for each iteration of the "outer loop".

Example:

The pass Statement

for loops cannot be empty, but if you for some reason have a for loop with no content, put in the pass statement to avoid getting an error.

Example: