Converting Hex to RGB value in Python

Working off Jeremy's response here: https://stackoverflow.com/questions/214359/converting-hex-color-to-rgb-and-vice-versa I was able to get a python program to convert preset colour hex codes (example #B4FBB8), however from an end-user perspective we can't ask people to edit code & run from there. How can one prompt the user to enter a hex value and then have it spit out a RGB value from there?

Here's the code I have thus far:

def hex_to_rgb(value):
    value = value.lstrip('#')
    lv = len(value)
    return tuple(int(value[i:i + lv // 3], 16) for i in range(0, lv, lv // 3))


def rgb_to_hex(rgb):
    return '#%02x%02x%02x' % rgb

hex_to_rgb("#ffffff")              # ==> (255, 255, 255)
hex_to_rgb("#ffffffffffff")        # ==> (65535, 65535, 65535)
rgb_to_hex((255, 255, 255))        # ==> '#ffffff'
rgb_to_hex((65535, 65535, 65535))  # ==> '#ffffffffffff'

print('Please enter your colour hex')

hex == input("")

print('Calculating...')
print(hex_to_rgb(hex()))

Using the line print(hex_to_rgb('#B4FBB8')) I'm able to get it to spit out the correct RGB value which is (180, 251, 184)

It's probably super simple - I'm still pretty rough with Python.

I believe that this does what you are looking for:

h = input('Enter hex: ').lstrip('#')
print('RGB =', tuple(int(h[i:i+2], 16) for i in (0, 2, 4)))

(The above was written for Python 3)

Sample run:

Enter hex: #B4FBB8
RGB = (180, 251, 184)

Writing to a file

To write to a file with handle fhandle while preserving the formatting:

fhandle.write('RGB = {}'.format( tuple(int(h[i:i+2], 16) for i in (0, 2, 4)) ))

You can use ImageColor from Pillow.

>>> from PIL import ImageColor
>>> ImageColor.getcolor("#23a9dd", "RGB")
(35, 169, 221)

Just another option: matplotlib.colors module.

Quite simple:

>>> import matplotlib.colors
>>> matplotlib.colors.to_rgb('#B4FBB8')
(0.7058823529411765, 0.984313725490196, 0.7215686274509804)

Note that the input of to_rgb need not to be hexadecimal color format, it admits several color formats.

You can also use the deprecated hex2color

>>> matplotlib.colors.hex2color('#B4FBB8')
(0.7058823529411765, 0.984313725490196, 0.7215686274509804)

The bonus is that we have the inverse function, to_hex and few extra functions such as, rgb_to_hsv.

A lazy option: webcolors package has a hex_to_rgb function.

PIL also has this function, in ImageColor.

from PIL import ImageColor

ImageColor.getrgb("#9b9b9b")

And if you want the numbers from 0 to 1

[i/256 for i in ImageColor.getrgb("#9b9b9b")]

This function will return the RGB values in float from a Hex code.

def hextofloats(h):
    '''Takes a hex rgb string (e.g. #ffffff) and returns an RGB tuple (float, float, float).'''
    return tuple(int(h[i:i + 2], 16) / 255. for i in (1, 3, 5)) # skip '#'

---

This function will return Hex code from RGB value.

def floatstohex(rgb):
    '''Takes an RGB tuple or list and returns a hex RGB string.'''
    return f'#{int(rgb[0]*255):02x}{int(rgb[1]*255):02x}{int(rgb[2]*255):02x}'

As HEX codes can be like "#FFF", "#000", "#0F0" or even "#ABC" that only use three digits. These are just the shorthand version of writing a code, which are the three pairs of identical digits "#FFFFFF", "#000000", "#00FF00" or "#AABBCC".

---

This function is made in such a way that it can work with both shorthands as well as the full length of HEX codes. Returns RGB values if the argument hsl = False else return HSL values.

import re

def hex_to_rgb(hx, hsl=False):
    """Converts a HEX code into RGB or HSL.
    Args:
        hx (str): Takes both short as well as long HEX codes.
        hsl (bool): Converts the given HEX code into HSL value if True.
    Return:
        Tuple of length 3 consisting of either int or float values.
    Raise:
        ValueError: If given value is not a valid HEX code."""
    if re.compile(r'#[a-fA-F0-9]{3}(?:[a-fA-F0-9]{3})?$').match(hx):
        div = 255.0 if hsl else 0
        if len(hx) <= 4:
            return tuple(int(hx[i]*2, 16) / div if div else
                         int(hx[i]*2, 16) for i in (1, 2, 3))
        return tuple(int(hx[i:i+2], 16) / div if div else
                     int(hx[i:i+2], 16) for i in (1, 3, 5))
    raise ValueError(f'"{hx}" is not a valid HEX code.')

---

Here are some IDLE outputs.

>>> hex_to_rgb('#FFB6C1')
(255, 182, 193)

>>> hex_to_rgb('#ABC')
(170, 187, 204)

>>> hex_to_rgb('#FFB6C1', hsl=True)
(1.0, 0.7137254901960784, 0.7568627450980392)

>>> hex_to_rgb('#ABC', hsl=True)
(0.6666666666666666, 0.7333333333333333, 0.8)

>>> hex_to_rgb('#00FFFF')
(0, 255, 255)

>>> hex_to_rgb('#0FF')
(0, 255, 255)

>>> hex_to_rgb('#0FFG')  # When invalid hex is given.
ValueError: "#0FFG" is not a valid HEX code.

The following function will convert hex string to rgb values:

def hex_to_rgb(hex_string):
    r_hex = hex_string[1:3]
    g_hex = hex_string[3:5]
    b_hex = hex_string[5:7]
    return int(r_hex, 16), int(g_hex, 16), int(b_hex, 16)

This will convert the hexadecimal_string to decimal number

int(hex_string, 16)

For example:

int('ff', 16) # Gives 255 in integer data type

There are two small errors here!

hex == input("")

Should be:

user_hex = input("")

You want to assign the output of input() to hex, not check for comparison. Also, as mentioned in comments (@koukouviou) don't override hex, instead call it something like user_hex.

Also:

print(hex_to_rgb(hex()))

Should be:

print(hex_to_rgb(user_hex))

You want to use the value of hex, not the type's callable method (__call__).

All the answers I've seen involve manipulation of a hex string. In my view, I'd prefer to work with encoded integers and RGB triples themselves, not just strings. This has the benefit of not requiring that a color be represented in hexadecimal-- it could be in octal, binary, decimal, what have you.

Converting an RGB triple to an integer is easy.

rgb = (0xc4, 0xfb, 0xa1) # (196, 251, 161)

def rgb2int(r,g,b):
    return (256**2)*r + 256*g + b

c = rgb2int(*rgb) # 12909473
print(hex(c))     # '0xc4fba1'

We need a little more math for the opposite direction. I've lifted the following from my answer to a similar Math exchange question.

c = 0xc4fba1

def int2rgb(n):
    b = n % 256
    g = int( ((n-b)/256) % 256 )      # always an integer
    r = int( ((n-b)/256**2) - g/256 ) # ditto
    return (r,g,b)

print(tuple(map(hex, int2rgb(c)))) # ('0xc4', '0xfb', '0xa1')

With this approach, you can convert to and from strings with ease.

The problem with your approach is that a user can input a hex code in many formats such as:

• With or without a hash symbol (#ff0000 or ff0000)
• Uppercase or lowercase (#ff0000, #FF0000)
• Including or not including transparency (#ffff0000 or #ff0000ff or #ff0000)

colorir can be used to format and convert between color systems:

from colorir import HexRGB, sRGB
user_input = input("Enter the hex code:")
rgb = HexRGB(user_input).rgb()  # This is safe for pretty much any hex format

Try this:

def rgb_to_hex(rgb):
    return '%02x%02x%02x' % rgb

Usage:

>>> rgb_to_hex((255, 255, 195))
'ffffc3'

---

And for the reverse:

def hex_to_rgb(hexa):
    return tuple(int(hexa[i:i+2], 16)  for i in (0, 2, 4))

Usage:

>>> hex_to_rgb('ffffc3')
(255, 255, 195)