Print string and variable contents on the same line in R

Question

Is there a way to print text and variable contents on the same line? For example,

wd <- getwd()
print("Current working dir: ", wd)

I couldn't find anything about the syntax that would allow me to do this.

agstudy · Accepted Answer · 2014-04-24T06:38:06.250

378

You can use paste with print

print(paste0("Current working dir: ", wd))

or cat

cat("Current working dir: ", wd)

edited Apr 24 '14 at 06:38

answered Mar 23 '13 at 17:08

agstudy

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You probably want `sep = ''` or you'll get an extra space. – hadley Mar 25 '13 at 23:49
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Using `cat()` I get a `NULL` at the end :( – ragesz Jun 13 '16 at 12:19
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@ragesz i only get null on the end if you put the cat inside of a print like: `print(cat("test", var))` which should be `cat("test", var)` – Spidfire Jun 16 '16 at 14:36

krlmlr · Answer 2 · 2019-05-13T21:00:08.717

76

{glue} offers much better string interpolation, see my other answer. Also, as Dainis rightfully mentions, sprintf() is not without problems.

There's also sprintf():

sprintf("Current working dir: %s", wd)

To print to the console output, use cat() or message():

cat(sprintf("Current working dir: %s\n", wd))
message(sprintf("Current working dir: %s\n", wd))

edited May 13 '19 at 21:00

answered Mar 23 '13 at 17:18

krlmlr

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Another nice option! This is very similar to other scripting languages and very convenient if you have a text where you want to implement multiple variables. Thanks! – Mar 23 '13 at 17:28
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by far the most convenient option, especially if you're composing a function argument. with paste it quickly becomes an unreadable mess. – user27636 Dec 26 '15 at 12:23
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Note that `sprintf` does not print, it just formats the string. Something like print(sprintf(...)) is necessary inside scripts. – C.H.S. Oct 11 '16 at 12:50

score 28 · Answer 3 · answered Mar 23 '13 at 17:14

28

Or using message

message("Current working dir: ", wd)

@agstudy's answer is the more suitable here

answered Mar 23 '13 at 17:14

Jilber Urbina

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Wow very straightforward! – Jane Kathambi May 08 '21 at 08:50

score 21 · Answer 4 · answered Feb 21 '15 at 20:39

Easiest way to do this is to use paste()

> paste("Today is", date())
[1] "Today is Sat Feb 21 15:25:18 2015"

paste0() would result in the following:

> paste0("Today is", date())
[1] "Today isSat Feb 21 15:30:46 2015"

Notice there is no default seperator between the string and x. Using a space at the end of the string is a quick fix:

> paste0("Today is ", date())
[1] "Today is Sat Feb 21 15:32:17 2015"

Then combine either function with print()

> print(paste("This is", date()))
[1] "This is Sat Feb 21 15:34:23 2015"

Or

> print(paste0("This is ", date()))
[1] "This is Sat Feb 21 15:34:56 2015"

As other users have stated, you could also use cat()

krlmlr · Answer 5 · 2019-05-13T21:08:48.310

15

The {glue} package offers string interpolation. In the example, {wd} is substituted with the contents of the variable. Complex expressions are also supported.

library(glue)

wd <- getwd()
glue("Current working dir: {wd}")
#> Current working dir: /tmp/RtmpteMv88/reprex46156826ee8c

^{Created on 2019-05-13 by the reprex package (v0.2.1)}

Note how the printed output doesn't contain the [1] artifacts and the " quotes, for which other answers use cat().

edited May 13 '19 at 21:08

answered May 13 '19 at 20:59

krlmlr

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I like this glue package because the format of printing numbers and strings in the same sentence is similar to python's syntax! – Jane Kathambi May 08 '21 at 08:50

score 9 · Answer 6 · answered Jun 21 '15 at 14:38

As other users said, cat() is probably the best option.

@krlmlr suggested using sprintf() and it's currently the third ranked answer. sprintf() is not a good idea. From R documentation:

The format string is passed down the OS's sprintf function, and incorrect formats can cause the latter to crash the R process.

There is no good reason to use sprintf() over cat or other options.

Codemaker2015 · Answer 7 · 2019-01-15T15:02:44.870

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you can use paste0 or cat method to combine string with variable values in R

For Example:

paste0("Value of A : ", a)

cat("Value of A : ", a)

edited Jan 15 '19 at 15:02

answered Nov 29 '18 at 11:37

Codemaker2015

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score 1 · Answer 8 · answered Sep 25 '20 at 08:42

1

A trick would be to include your piece of code into () like this:

(wd <- getwd())

which means that the current working directory is assigned to wd and then printed.

answered Sep 25 '20 at 08:42

AlexB

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Print string and variable contents on the same line in R

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