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 [[alternative HTML version deleted]]
I think once upon a time this was found to be OS-dependent since it calls the system's C sprintf() -- I get the leading zeros on Mac. I presume you're on Windows? Michael 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 > > ? ? ? ?[[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
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
Please do reply to the list -- I'm not on Windows so someone else will
have to pick the question up to help you out.
It's not great, but you could do something like
zeroPad <- function(str, len.out, num.zeros = len.out[1] - nchar(str)){
paste0(paste(rep("0", num.zeros), collapse = ""), str)
}
as a temporary work-around. Probably possible to vectorize that pretty
easily as well.
Best,
Michael
On Tue, May 22, 2012 at 2:50 PM, Hui Du <Hui.Du at dataventures.com>
wrote:> Thank you for your replay. Yes, I am on windows.
>
> Best Regards,
> Hui Du
>
> Data Ventures Inc
>
> -----Original Message-----
> From: R. Michael Weylandt [mailto:michael.weylandt at gmail.com]
> Sent: Tuesday, May 22, 2012 11:49 AM
> To: Hui Du
> Cc: r-help at r-project.org
> Subject: Re: [R] pad leading zeros in front of strings
>
> I think once upon a time this was found to be OS-dependent since it
> calls the system's C ?sprintf() ?-- I get the leading zeros on Mac. I
> presume you're on Windows?
>
> Michael
>
> 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
>>
>> ? ? ? ?[[alternative HTML version deleted]]
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.