Python programming-for
loops

Quick revision
 What is a list?
 Difference between list and a variable
 Can list store data of multiple types?
 What is used to iterate over a list?
 How to calculate length of list?
 Are strings stored as lists in python?

What is for loop???
 The for loop in Python is used to iterate over
a sequence (list, tuple, string) or other
iterable objects.
 Iterating over a sequence is called traversal.

2 types of writing for loops
1.Getting each element of the sequence
2.Range (): By generating range of numbers and
use these numbers as indexes to access
sequences.

Lets dive in type 1 of for loop

Syntax of for loop

Example

Flowchart of for loop

Iterating over string

Example 2:For loop to calculate sum
of elements in a list

The break statement
 Exit the loop when x is "banana", but this time the
break comes before the print:

Continue keyword
 With the continue statement we can stop the
current iteration of the loop, and continue with
the next:

Type 2 of for loop

The range() function
 We can generate a sequence of numbers using
range() function. range(10) will generate
numbers from 0 to 9 (10 numbers).
 We can also define the start, stop and step size
as range(start,stop,step size). step size defaults
to 1 if not provided.
 To force this function to output all the items, we
can use the function list().

Example

Example to use range() in for loop

 Syntax : range(start index, end index, step size)

Sample problems
 Print elements of a 1 dimensional list.
 Print elements of 2 dimensional list.
 Print even elements in a list.

This work is licensed under a Creative Commons
Attribution-ShareAlike 3.0 Unported License.
It makes use of the works of Mateus Machado Luna.