I have numbers like this that need leading zero\'s removed.
Here is what I need:
00000004334300343 -> 4334300343
00000004334300343
4334300343
000
\b0+\B will do the work. See demo \b anchors your match to a word boundary, it matches a sequence of one or more zeros 0+, and finishes not in a word boundary (to not eliminate the last 0 in case you have only 00...000)
\b0+\B
\b
0+
0
00...000