Why replacing colors process in numpy array never ends

Question

I am reading a .gif image using the imageio library in Python (which reads the .gif format as a list of frames, each are numpy arrays). I want to replace all the RGB colors in the .gif image with a certain fixed color (to possibly use an if statement later to change some parts of the image).

The data are on the form of something like [[23 234 23 24], [34, 46, 57 255]]...

This is my code:

gifimage = imageio.mimread(inputgif)
for x in range(len(gifimage)):
  shape = gifimage[x].shape
  for l in range(0, shape[0]):
    for y in range(0, shape[1]):
      gifimage[x][l][y] = [50, 205, 50, 255] #255 is just the alpha channel which I can ignore.

Also tried:

for x in range(len(gifimage)):
  shape = gifimage[x].shape
  for l in range(0, shape[0]):
    for y in range(0, shape[1]):
      gifimage[x][l][y][0] = 50
      gifimage[x][l][y][1] = 205
      gifimage[x][l][y][2] = 50
      gifimage[x][l][y][2] = 255

But when I run it, it never ends. Why is that?

Grr · Accepted Answer · 2017-04-25 12:04:10Z

1

For one thing you can eliminate some for loops. If you just want to reassign all of the pixels to a single color you can do the following:

gifimage[:][:][:] = [50, 205, 50, 255]

Just to be sure I follow, this will change every pixel to lime green.

answered Apr 25, 2017 at 12:04

Grr

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2 Comments

Madno Over a year ago

Thank you! This is what I was looking for. Now I can play with it by if statements to replace only the ones I desire.

Madno Over a year ago

But I am also curious to know why my for loops didn't work?

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