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I would like to format output of a print statement so that elements in the print statement are separated by a small uniform gap, a gap of either 1, 3 or 5 empty spaces. Is that possible?

In the example below, I think all of the elements in the print statement are assumed to be as long as the first element in the print statement (here either as long as aa1 or aa2).

The print.gap statement does not result in the desired format. It simply adds an additional constant number of spaces between each element.

aa1 <- 'abcdefghijklmnopqrstuvwxyz'
aa2 <- 'abc'

bb  <- 10
cc  <- 222

print(c(aa1,bb,cc))

# [1] "abcdefghijklmnopqrstuvwxyz" "10"                         "222" 

print(c(aa2,bb,cc))

# [1] "abc" "10"  "222"

# desired output:

# [1] "abcdefghijklmnopqrstuvwxyz"   "10"   "222" 
#
# or
#
# [1] "abcdefghijklmnopqrstuvwxyz"   10   222

Thank you for any advice. Perhaps I must use a cat statement and sprintf instead of a print statement. Maybe some variation of this: How to print R variables in middle of String

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Mark Miller
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    I am not sure what you are looking for--you want a fixed separation of 1, 3 or 5 spaces, the same every time, or varying? Otherwise `sprintf()` or `paste(aa1,bb,cc,sep=" ")` might be what you need. – ako Oct 02 '12 at 22:52

2 Answers2

4

This will get you partway there:

x <- c(aa1,bb,cc)

options(useFancyQuotes = FALSE)
cat(paste(dQuote(x), collapse="   "), "\n")
# "abcdefghijklmnopqrstuvwxyz"   "10"   "222"

I say "partway" because the code above doesn't take care of line-wrapping: if you hand it a very long vector of characters strings, they will all be cat'd to a single very long non-wrapping line...

Edited to show one method of wrapping the lines:

You can get line-wrapping by using a combination of strwrap() (thanks @mnel) and gsub(), :

xs <- c(x,x,x,x)

cat(gsub("\" \"", "\"   \"", 
    strwrap(paste(dQuote(xs), collapse=" "), 70)), sep="\n")
# "abcdefghijklmnopqrstuvwxyz"   "10"   "222"   "abcdefghijklmnopqrstuvwxyz"
# "10"   "222"   "abcdefghijklmnopqrstuvwxyz"   "10"   "222"
# "abcdefghijklmnopqrstuvwxyz"   "10"   "222"

(The call to gsub() is needed if more than one space is needed between the vector elements, because strwrap() destroys whitespace in the input.)

Josh O'Brien
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  • Use `strwrap` to wrap at some sensible length (such as `options()$width`) eg `cat(strwrap(paste(rep(dQuote(x),10), collapse=" "), 80), "\n")` – mnel Oct 02 '12 at 23:16
  • @mnel. Nice. Unfortunately, `cat(strwrap(paste(rep(dQuote(x),10), collapse=" "), 80), sep="\n")` appears to only leave one space between elements, no matter how many you specify in the `collapse=` argument... Any idea of a way around that? – Josh O'Brien Oct 02 '12 at 23:22
  • I was just trying to write it up as an answer and finding the same issue. Still looking for a solution – mnel Oct 02 '12 at 23:33
2

I'll post my comment as an answer

you can create your own print.character method and use strwrap to wrap to sensible line length.

Unfortunately strwrap destroys all whitespace and replaces it with a single space

print.character <- function(x, width = getOption('width'), .sep = '  '){
  cat(paste(strwrap(paste(dQuote(x), collapse = .sep, sep =.sep), width),  
  collapse = '\n'), '\n')
}
x <- c(aa1,bb,cc)
print(x)
## "abcdefghijklmnopqrstuvwxyz" "10" "222"
print(rep(x,10))
## "abcdefghijklmnopqrstuvwxyz" "10" "222" "abcdefghijklmnopqrstuvwxyz" "10" "222"
## "abcdefghijklmnopqrstuvwxyz" "10" "222" "abcdefghijklmnopqrstuvwxyz" "10" "222"
## "abcdefghijklmnopqrstuvwxyz" "10" "222" "abcdefghijklmnopqrstuvwxyz" "10" "222"
## "abcdefghijklmnopqrstuvwxyz" "10" "222" "abcdefghijklmnopqrstuvwxyz" "10" "222"
## "abcdefghijklmnopqrstuvwxyz" "10" "222" "abcdefghijklmnopqrstuvwxyz" "10" "222"

It will not work as expected with whitespace within the character variables

print('Does not work  with strings with  variable spaces that you \n might \t \t \t want to keep')
"Does not quite work with strings with variable spaces that you might want to keep"
mnel
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  • Here it is. I think this belongs with your answer rather than mine, since `strwrap()` was your idea, so feel free to edit yours to add it if you think it works well enough: `cat(gsub(" ", " ", strwrap(paste(rep(dQuote(x),10), collapse=" "), 70)), sep="\n")`. – Josh O'Brien Oct 03 '12 at 02:29