Delphi: Add leading zeros to a number

Sometimes we want to display a number with leading zeros using Delphi or Lazarus, for example, in case that the numbers become double digits at some point and we directly want to start at 01, 02 and so on.

Fortunately there is a simple function which can do this for us:

str := Format('%.*d', [length, number]);
str := Format('%.*d', [3, 7]);
// str is '007'

The two required parameters are the number of places / leading zeros that we want to have (length) and the number as integer, we want to rewrite (number). The return value is a string.

In the second line you can see an example: When we call the function with the parameters 3 and 7, we get '007'.