Using a list in Python
problem
You are learning Python and wish to use a list of data instead of single data variables. In this post we will see how to create a list of numbers.
SOLUTION
numbers = [1,2,3,4,5,6,7,8,9,10]
Instead of having 10 different variables, we have only 1. We can access each individual number by using its index. For example to retrieve number 1, we use index 0 as follows:
numbers = [1,2,3,4,5,6,7,8,9,10]
one = numbers[0] # use index to retrieve positional item - starting from 0
print(numbers[0]) # will print 1
running
We can add this code in a .py file and execute by using the python compiler. Also, let’s add a print statement to make it show the list as follows:
numbers = [1,2,3,4,5,6,7,8,9,10]
print(numbers)
output
Simply the print() function shows the list of numbers without any particular format.
Changing one item value
By using the index [] we can print or amend a particular item in the list. To amend/ change the value of a number we use the assignment operator as follows:
numbers = [1,2,3,4,5,6,7,8,9,10]
numbers[0] = 0
print(numbers)
output
The number at index 0 (the first one) has now changed to 0 from 1.
sorting the list
Let’s suppose we have a list of numbers and we need to put the numbers in order from the lowest to the greatest, also known as sorting (in ascending order).
numbers = [2,-1,10,1,0,100,5,3,0]
numbers.sort()
print(numbers)
output
SORTING – DESCENDING ORDER
numbers = [1,2,3,4,5,6,7,8,9,10]
numbers.sort(reverse=True)
print(numbers)
output
By passing the key-value pair reverse=True the sorting is done in descending order, from the greatest to the lowest.
conclusion
In this post we saw how easy it is to create a list of numbers in Python and also how to sort it in ascending or descending order.
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Ellion
Professional IT consultant, writer, programmer enthusiast interested in all sorts of coding.
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