How to exlcude grey colour code from the file

Question

and parsing a HTML file. But i need to exclude grey color, i did it for black as if now but the grey color have alot of variation to give in if condition may i know how can i use it.

if style.find("color")>=0:
        aux = style[style.find("color"):]
        aux = aux[0:aux.find(";") + 1]
        
        if aux.find('#000000') < 0 and aux.find('black') < 0 and aux.find('#000') < 0: 
            use_raw = '%s%s' % (use_raw, aux)

This how i am exlcuding black, but here i want to exclude grey too.

"pure" grey always has the same value for RGB values, you can split the values `000000` into 3 sets of 2 digits, each set for each color, if the 3 sets are equal, you have grey. — Dalvenjia, Apr 25 '17 at 21:42
But, in python we are not able to split the value, as it throwing a error, that it should be str — , Apr 25 '17 at 21:46
you can use slices. Strip the `#` and check that `x[:2] == x[2:4] == x[4:]` where x is the hex color. — Dalvenjia, Apr 25 '17 at 21:49

score 2 · Accepted Answer · edited May 23 '17 at 11:54

You can use a regex. ^#([a-fA-F0-9]{1,2})\1\1$ will identify all 6-digit and 3-digit gray hex colors.

Explanation

Identifying 'grey'

All grey hex color codes have 3 sets of 2 digits or 3 identical digits. e.g. #151515, #1C1C1C, #2E2E2E, #424242, #555, #EEE..... and this is how we can identify them as grey.

Determining if string meets 'grey' format

Therefore I would use a regex. The following regular expression will match all strings, that start with a #, and contain 3 identical consecutive sets of 2 digit alpha-numeric characters. Hence match all greys.

^#([a-fA-F0-9]{1,2})\1\1$

Applying with Python

import re
pattern = re.compile("^#([a-fA-F0-9]{1,2})\1\1$")
pattern.match(aux)

See the Python documentation on regular expressions: https://docs.python.org/3/library/re.html

References:

You can change your regex to `^#([a-fA-F0-9]{1,2})\1\1$` and it should work for three-digit colors. — Blender, Apr 25 '17 at 23:03
Didn't think of that, thanks @Blender! I've amended the answer — Alicia Sykes, Apr 25 '17 at 23:23
Which part isn't working? I need something more specific to be able to help :) — Alicia Sykes, Apr 27 '17 at 11:45

score 0 · Answer 2 · answered Apr 25 '17 at 22:01

You could possibly do something like

    for i in ["lightgray", "lightgrey", "silver", "darkgray", "darkgrey",
            "gray", "grey", "dimgray", "dimgrey", "darkslategrey"]:
        if aux.find(i)<0:
            use_raw = '%s%s' % (use_raw, aux)
    for i in range(1,256):
        if aux.find('#%02x%02x%02x'%(i,i,i))<0 and format(i<<16 | i<<8 | i, '06X')<0 and format(i<<16 | i<<8 | i, '06x')<0:
            use_raw = '%s%s' % (use_raw, aux)

You could probably make the code smaller and more efficient, but that's a simple answer, I guess. (This does include only strictly grey colour. It does not allow for slight variations.)

@RachitAgarwal, the list is to cover all bases. The for function with the range is designed to cover all hexa 3-digit, 6-digit, and RGB colour codes. — Withaika, Apr 26 '17 at 21:39