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 c

Answer 1

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()

Answer 2

{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))

Answer 3

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().

Answer 4

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.

Answer 5

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.

Answer 6

Or using message

message("Current working dir: ", wd)

@agstudy's answer is the more suitable here