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c#zero-pad

Simple and elegant way to zero-pad a value in C#

I have to fix malformed zipcodes. The people who exported the data treated the zipcode as a numeric and as a result New Jersey and Puerto Rico zipcodes, which begin with a leading zero and two leading zeroes respectively, have been truncated.

They're supposed to be all five characters (no zip+4 data is involved). I know how to zero-pad brute-force by getting the length and prepending the appropriate number of zeroes to the string, but is there a more elegant way that draws on the "native" features of C#? For example, can a mask be applied that would turn "9163" into "09163" and "904" into "00904" without my having to get the length of the value?

Solution

  • If you have an integer value, use the composite format string to ensure padding:

    var padded1 = 1.ToString("D5");

    The number after D is for the length you need the value to be in.