Converting an RGB color tuple to a hexidecimal string

2018-01-16

An answer to this question on Stack Overflow.

Question

I need to convert (0, 128, 64) to something like this "#008040". I'm not sure what to call the latter, making searching difficult.

Answer

Here is a more complete function for handling situations in which you may have RGB values in the range [0,1] or the range [0,255].

def RGBtoHex(vals, rgbtype=1):
  """Converts RGB values in a variety of formats to Hex values.
     @param  vals     An RGB/RGBA tuple
     @param  rgbtype  Valid valus are:
                          1 - Inputs are in the range 0 to 1
                        256 - Inputs are in the range 0 to 255
     @return A hex string in the form '#RRGGBB' or '#RRGGBBAA'
"""
  if len(vals)!=3 and len(vals)!=4:
    raise Exception("RGB or RGBA inputs to RGBtoHex must have three or four elements!")
  if rgbtype!=1 and rgbtype!=256:
    raise Exception("rgbtype must be 1 or 256!")
  #Convert from 0-1 RGB/RGBA to 0-255 RGB/RGBA
  if rgbtype==1:
    vals = [255*x for x in vals]
  #Ensure values are rounded integers, convert to hex, and concatenate
  return '#' + ''.join(['{:02X}'.format(int(round(x))) for x in vals])
print(RGBtoHex((0.1,0.3,  1)))
print(RGBtoHex((0.8,0.5,  0)))
print(RGBtoHex((  3, 20,147), rgbtype=256))
print(RGBtoHex((  3, 20,147,43), rgbtype=256))