Decorating Hex function to pad zeros

Starting with Python 3.6, you can:

>>> value = 42
>>> padding = 6
>>> f"{value:#0{padding}x}"
'0x002a'

for older python versions use the .format() string method:

>>> "{0:#0{1}x}".format(42,6)
'0x002a'

Explanation:

{   # Format identifier
0:  # first parameter
#   # use "0x" prefix
0   # fill with zeroes
{1} # to a length of n characters (including 0x), defined by the second parameter
x   # hexadecimal number, using lowercase letters for a-f
}   # End of format identifier

If you want the letter hex digits uppercase but the prefix with a lowercase ‘x’, you’ll need a slight workaround:

>>> '0x{0:0{1}X}'.format(42,4)
'0x002A'

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