dechex没有显示前两个零（rgb到十六进制php）[重复]

Question

This question already has an answer here:

• PHP Binary to Hex with leading zeros 3 answers

I use this php script to get the rgb color from a jpg file:

source: https://stackoverflow.com/a/36321726/8144877

the problem is when the rgb color look like this: rgb(0, 23, 110) then the script returns this hex: 176e and not 00176e

I see that the script not showing the first two zeros, is there a way to showing all the zeros when using dechex to convert rgb to hex?

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Answer 1

Yes, there's a way, str_pad function is there to help you:

str_pad("176e", 6, "0", STR_PAD_LEFT); // "00176e"

Arguments:

1. input string
2. expected length
3. padding character
4. padding mode - in your case STR_PAD_LEFT is needed to pad on the left side