Lists
A Simple List
Besides numbers and text, variables can contain a collection of items called a list
- For example
- a collection (list) of colors: colors = ['green', 'blue', 'red', 'yellow']
- Once we create a list, we can use it in a for loop as follows:
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- The full code can be found here: https://trinket.io/python/94de1feac8
What Else Can We Do With a List?
Let's start with a list: colors = ['green', 'blue', 'red', 'yellow']
Operation | Result |
---|---|
colors.append('green') | colors = ['green', 'blue', 'red', 'yellow“, 'green'] |
colors.insert(2, 'green') | colors = ['green', 'blue', 'green', 'red', 'yellow“, 'green'] |
colors.remove('green') | colors = ['blue', 'green', 'red', 'yellow“, 'green'] |
color = colors.pop(2) | color = 'red', colors = ['blue', 'green', 'yellow', 'green'] |
color = colors.pop() | color = 'green', colors = ['blue', 'green', 'yellow'] |
colors.sort() | colors = ['blue', 'green', 'yellow'] |
colors.reverse() | colors = ['yellow', 'green', 'blue'] |
colors.clear() | colors = [] |
Taking It a Step Further
- Find the number of elements in a list:
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Challenge
- Get a random number of colors from the user
- hint: color = input('Enter a color: ')
- Store the color in a list of colors
- Draw the polygons, one in each color, in a similar manner to the four squares.
- Let the number of sides of each polygon be equal to the number of colors that the user entered
- hint: # of sides = len(colors)
- Calculate the angle needed to draw a polygon
- hint: angle = 360 / # of sides
- Loop through all of the colors in the list you created
- hint:
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for color in colors: # set the color # begin fill # draw polygon # end fill # hide the turtle when done.
- hint:
- Let the number of sides of each polygon be equal to the number of colors that the user entered
What happens if the user only enters two colors? Can you add a check?
Need some help? Take a look here: https://trinket.io/python/06ab63c75f