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| 184_notes:lists [2022/04/20 15:08] – woodsna1 | 184_notes:lists [2022/05/07 01:20] (current) – woodsna1 | ||
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| ====== Coding: Lists ====== | ====== Coding: Lists ====== | ||
| - | We often need a way to represent a group of objects or values in code. Python makes this easy with lists. A list gives a name to a collection of any Python objects. In Glowscript, we often use lists that include spheres, arrows, rings, and other shapes. Creating a list is easy: | + | We often need a way to represent a group of objects or values in code. Python makes this easy with lists. A list gives a name to a collection of any Python objects. |
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| + | In Glowscript, we often use lists that include spheres, arrows, rings, and other shapes. Creating a list is easy: | ||
| < | < | ||
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| </ | </ | ||
| - | You can think of a list like a column in an excel spreadsheet, | + | You can also access each bucket in a list to update or retrieve the object within it. One way is by using list indexing. Indices in a Python list start at 0 for the first element: |
| < | < | ||
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| </ | </ | ||
| - | To change the value in a bucket, simply use = to assign to it: | + | To change the value in a bucket, simply use "=" |
| < | < | ||
| list_of_numbers[0] = 250 # Change the first element | list_of_numbers[0] = 250 # Change the first element | ||
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| ===== Lists and For Loops ===== | ===== Lists and For Loops ===== | ||
| + | ==== Lecture Video ==== | ||
| + | |||
| + | {{youtube> | ||
| We often want to move through a list and read or change each value one-by-one. The easiest way to iterate through a list in Python is using a for loop. | We often want to move through a list and read or change each value one-by-one. The easiest way to iterate through a list in Python is using a for loop. | ||
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| index = 0 | index = 0 | ||
| - | while index < len(list_of_numbers): | + | while index < len(list_of_numbers): |
| - | list_of_numbers[index] += 1 | + | list_of_numbers[index] += 5 # Increase each number by 5 |
| - | index += 1 | + | index += 1 # Increment the counter variable |
| </ | </ | ||