How do you “chomp” a string in Vim?

Question

Suppose you run the following piece of vimscript:

let @z = system("date")

This will put a string version of the current date into the z register, but the string will end with a newline that I don’t want. Is there a built-in way (similar to Perl’s chomp) to get rid of a string’s trailing newlines?

Ingo Karkat · Accepted Answer

You can use substitute(), or define a function:

function! Chomp(string)
    return substitute(a:string, 'n+$', '', '')
endfunction

This variant will call system for you and then chomp the result:

function! ChompedSystem( ... )
    return substitute(call('system', a:000), 'n+$', '', '')
endfunction

(This function is also available in my ingo-library plugin as ingo#system#Chomped.)

pR0Ps · Answer

Vim v8.0.1630 added a trim() function that removes characters (by default whitespace) from the end or beginning (both by default) of strings:
let @z = trim(system("date"))

For more details see :help trim()

joeytwiddle · Answer

Christian Brabandt has listed a number of different methods over on superuser.com.

I like this one because it is short:

let @z = system("date")[:-2]

romainl · Answer

let @z = systemlist('date')[0]

removes the newline for you.

How do you “chomp” a string in Vim?

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