Manipulating Varables

Functions and Iterables

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Creating for loops and putting it into a function

  • Since we just introduced a list, one of the most useful parts of a list is that they are an iterable

An iterable is a collection of data that you can move through using a for loop

For Loop Syntax in python

            

                
                    # Example 1
# For loop through a list of Numbers

lst = [1,2,3,4]

# "Iterate" through each number in the list
for number in lst:

  # Print the number during each iteration
  print(number)

You can iterate through many different objects including strings

This would be a good time to go ahead and play around with the following code segments in an IDE. Run each segment separately, and try to understand what is going on in each

            

                
                    # Example 2
# For loop through each letter in the string
string = 'Hello'

# Iterate through each letter in the string
for letter in string:

  # Print each letter during the iterations
  print(letter)

Printing words in a list

            

                
                    # Declare the list of words
lst_string = ['Hello','World']

# Iterate through each word in the list
for word in lst_string:

  # Print the word during each iteration
  print(word)

The range() Function

To loop through a set of code a specified number of times we can use the range() function.

The range() function returns a sequence of numbers, starting from 0 by default, and increments by 1 (by default), and ends at a specified number.

            

                
                    # Create an iterable using range
for x in range(6):

  # print the value of the iterable during each loop
  print(x)
  • The range() function defaults to 0 as a starting value, however it is possible to specify the starting value by adding a parameter: range(2, 6), which means values from 2 to 6 (but not including 6):
            

                
                    # Start at number 2 and go through 5
for x in range(2,6):

  print(x)
  • The range() function defaults to increment the sequence by 1, however it is possible to specify the increment value by adding a third parameter: range(2, 30, 3)
            

                
                    # Sequence starting at 2 going to 30 and jumping by 3
for x in range(2, 30, 3):

  print(x)