Looping through arrays in Python3

Question

Suppose I have a list of five different colours, colour = ['red', 'blue', ...] etc. I then want to create a loop for making an arbitrary amount of circles defined by the tkinter modules. That would mean something like

def Circles():
    y = 0
    x = 0
    while y <= 900 and x <= 900:
        x = x + 100
        y = y + 100
        w.create_oval(x, y, 0, 0, fill='red')

How would I include a loop for that fill='red' part, where I instead want fill=colour[N], where N would change in a loop? So the first circle would be red, next blue, next green etc? I also know that these ones overlap and I will try to make them not overlap, but that's not the question here.

Since x and y are the same, use 1 variable and use a for loop: for x in range(0,1000,100): — Chris_Rands
– Chris_Rands, Commented Mar 10, 2017 at 15:10
Also as an aside, you have a list of colors, definitely not an array. — kingstante
– kingstante, Commented Mar 10, 2017 at 15:11
Hello Edwin and welcome to the site. We like to keep questions to the point here, so I trimmed yours down a bit. Feel free to edit again if you'd like. — MackM
– MackM, Commented Mar 10, 2017 at 15:12

DevLounge · Accepted Answer · 2017-03-10 15:15:47Z

3

I would use itertools.cycle. Also as you increment both x and y by 100, up to 900, use range.

from itertools import cycle
colors = ['red', 'blue', 'yellow', 'green', 'orange']

def Circles():
    cycling_colors = cycle(colors)
    for i in range(0, 901, 100):
        w.create_oval(i, i, 0, 0, fill=next(cycling_colors))

edited Mar 10, 2017 at 15:15

answered Mar 10, 2017 at 15:12

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3 Comments

Jon Clements Over a year ago

It's better to use next(cycling_colors)... (changes between 2.x and 3.x semantics) - next(...) will work on both

Jon Clements Over a year ago

I'd probably also be tempted to do for i, c in zip(range(0, 901, 100), cycle(colors)): w.create_oval(i, i, 0, 0, fill=c) but given we don't know if it's 2.x or 3.x, on 2.x you'd definitely need izip or else you'd never exit the loop :)

Edwin Carlsson Over a year ago

Thank you! I will try to make sense of the syntax of itertools!

Dmitry · Accepted Answer · 2017-03-10 15:09:54Z

1

You can use this way, if you want to make nested loop:

colours = ['red', 'blue', 'green']

def Circles():
    y = 0
    x = 0
    while y <= 900 and x <= 900:
        x = x + 100
        y = y + 100
        for color in colours:
            w.create_oval(x, y, 0, 0, fill=colour)

Circles()

answered Mar 10, 2017 at 15:09

Dmitry

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Comments

Keerthana Prabhakaran · Accepted Answer · 2017-03-10 15:10:36Z

0

def Circles():
    y = 0
    x = 0
    while y <= 900 and x <= 900:
        x = x + 100
        y = y + 100
        #iterate the colour list
        for colo in colour:
            w.create_oval(x, y, 0, 0, fill=colo)

Hope it helps!

answered Mar 10, 2017 at 15:10

Keerthana Prabhakaran

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Comments

Frank-Rene Schäfer · Accepted Answer · 2017-03-10 15:22:07Z

0

I assume you may want to iterate over the plane of x an y. As for color, agreed, cycle is the right approach for the colors.

from itertools import cycle
def gen():
   color_cyclist = cycle('red', 'blue', 'green')
   for x in range(0,1000, 100):
       for y in range(0, 1000, 100):
           yield x, y, next(color_cyclist)

for x, y, color in gen():
    w.create(x, y, 0, 0, fill=color)

edited Mar 10, 2017 at 15:22

answered Mar 10, 2017 at 15:13

Frank-Rene Schäfer

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1 Comment

Edwin Carlsson Over a year ago

I tried that for x and for y loop on my own, before I came here. Python crashed when I tried it! Yours works just fine. Seems I need time :)

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