[R] pad leading zeros in front of strings

[Sarah Goslee]

Hi,

I think it's because " " is used to pad strings, while 0 is used to
pad numbers*. If your values are always numeric, but stored as
strings, you could use:

> x <- "123"
> sprintf("%05d", as.numeric(x))
[1] "00123"


* From ?sprintf:
    ‘0’ For numbers, pad to the field width with leading zeros.

I think some language implementations allow for specifying different
pad characters, but R's doesn't seem to.

Sarah

On Tue, May 22, 2012 at 2:41 PM, Hui Du <Hui.Du at dataventures.com> wrote:
> Dear All,
>
> This question sounds very simple but I don't know where I am wrong. I just want to pad leading zeros in some string, for example, "123" becomes "00123". What is wrong if I do following?
>
>> sprintf("%05s", "123")
> [1] "  123"
>
>
> It didn't return "00123", instead it padded with 'blank'.
>
>
> Thank you for your help in advance.
>
> HXD
>
>

-- 
Sarah Goslee
http://www.functionaldiversity.org