r - Strange interaction of apply with collapse argument to paste -

wanted clarification on unintended output got trying apply paste function collapse argument across data frame. can't find in documentation explicitly suggest should happen, though might missing something.

reproducible example:

data <- data.frame(a = 8:11, b = c('a', 'b', 'c', 'd'), stringsasfactors = false)  apply(data, 1, paste, collapse = ' ') 

desired output:

'8 a', '9 b', '10 c', '11 d' 

actual output:

' 8 a', ' 9 b', '10 c', '11 d' 

it seems in case r padding out digits of numbered vectors empty space. not happen if try same paste call outside of apply:

paste(data[1, ], collapse = ' ') 

result:

'8 a'