Python 8b - 2D Lists

Creating a List with Multiple Dimensions

Lists can be given another dimension to hold data that is related to each other.

A scenario: Three students have taken two Chemistry tests and their teacher has recorded the results in a 2 dimensional array (note that Python does not use arrays but uses lists instead):

To create this in Python:

Printing a 2D List

To print the whole list use a for loop to cycle through each record.

 

I have altered the normal i variable to be 'record' so it is more descriptive:

Use the index number to print a specific record.

 

Look at the table above and remember that Python starts counting at 0 so Edward is record 0, Bella 1 and Jacob 2:

To print a specific data value then you need to define the record number and then the data index.

When using 2D lists, the first value is the row and the second value is the column.

 

Use the table at the very top to help you visualise this:

Practice Task 1

Use the introduction at the top to help you create a 2D list with three friends in the first column, their age in the second column and their favourite colour in the third column.

Print the whole list.

Then print just the second person's information.

Example solution:

Searching Through a 2D List

To search through a multi-dimensional list then you need to search through each record and then each data element for a specific value:

Practice Task 2

Use the 2D list that you created in the first practice task.

Ask the user to enter a name.

Search through the list and print the record of that person's name.

Example solution:

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