在python中将元组列表表示为2d数组

Question

Say I have a list of tuples containing the RGB information of each pixels in an image from left to right, top to bottom.

[(1,2,3),(2,3,4),(1,2,4),(9,2,1),(1,1,1),(3,4,5)]

Assuming the width and height of the image is already know, is there a way I can represent the image using list of list?

For example, let's say the above list of tuples represent a 2x3 image, image[1][2] should give me the RGB tuple (3,4,5) .

Answer 1

Use the step argument in range (or xrange ):

>>> width = 2
>>> pixels = [(1,2,3),(2,3,4),(1,2,4),(9,2,1),(1,1,1),(3,4,5)]
>>> image = [pixels[x:x+width] for x in range(0,len(pixels),width)]
>>> image
[[(1, 2, 3), (2, 3, 4)], [(1, 2, 4), (9, 2, 1)], [(1, 1, 1), (3, 4, 5)]]

It will make x increment by the value of the step , instead of the default, which is 1. If you are familiar with Java, it's similar to:

for (int x=0; x<length; x = x+step)