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.
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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.
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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, you need to define the record number and then the data index.
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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.
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Print the whole list.
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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.
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Ask the user to enter a name.
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Search through the list and print the record of that person's name.
Example solution:
