I want to split a line in an R script over multiple lines (because it is too long). How do I do that?
Specifically, I have a line such as
setwd('~/a/very/long/path/here/that/goes/beyond/80/characters/and/then/some/more')
Is it possible to split the long path over multiple lines? I tried
setwd('~/a/very/long/path/here/that/goes/beyond/80/characters/and/
then/some/more')
with return key at the end of the first line; but that does not work.
Thanks.
Bah, comments are too small. Anyway, #Dirk is very right.
R doesn't need to be told the code starts at the next line. It is smarter than Python ;-) and will just continue to read the next line whenever it considers the statement as "not finished". Actually, in your case it also went to the next line, but R takes the return as a character when it is placed between "".
Mind you, you'll have to make sure your code isn't finished. Compare
a <- 1 + 2
+ 3
with
a <- 1 + 2 +
3
So, when spreading code over multiple lines, you have to make sure that R knows something is coming, either by :
leaving a bracket open, or
ending the line with an operator
When we're talking strings, this still works but you need to be a bit careful. You can open the quotation marks and R will read on until you close it. But every character, including the newline, will be seen as part of the string :
x <- "This is a very
long string over two lines."
x
## [1] "This is a very\nlong string over two lines."
cat(x)
## This is a very
## long string over two lines.
That's the reason why in this case, your code didn't work: a path can't contain a newline character (\n). So that's also why you better use the solution with paste() or paste0() Dirk proposed.
You are not breaking code over multiple lines, but rather a single identifier. There is a difference.
For your issue, try
R> setwd(paste("~/a/very/long/path/here",
"/and/then/some/more",
"/and/then/some/more",
"/and/then/some/more", sep=""))
which also illustrates that it is perfectly fine to break code across multiple lines.
Dirk's method above will absolutely work, but if you're looking for a way to bring in a long string where whitespace/structure is important to preserve (example: a SQL query using RODBC) there is a two step solution.
1) Bring the text string in across multiple lines
long_string <- "this
is
a
long
string
with
whitespace"
2) R will introduce a bunch of \n characters. Strip those out with strwrap(), which destroys whitespace, per the documentation:
strwrap(long_string, width=10000, simplify=TRUE)
By telling strwrap to wrap your text to a very, very long row, you get a single character vector with no whitespace/newline characters.
For that particular case there is file.path :
File <- file.path("~",
"a",
"very",
"long",
"path",
"here",
"that",
"goes",
"beyond",
"80",
"characters",
"and",
"then",
"some",
"more")
setwd(File)
The glue::glue function can help. You can write a string on multiple lines in a script but remove the line breaks from the string object by ending each line with \\:
glue("some\\
thing")
something
I know this post is old, but I had a Situation like this and just want to share my solution. All the answers above work fine. But if you have a Code such as those in data.table chaining Syntax it becomes abit challenging. e.g. I had a Problem like this.
mass <- files[, Veg:=tstrsplit(files$file, "/")[1:4][[1]]][, Rain:=tstrsplit(files$file, "/")[1:4][[2]]][, Roughness:=tstrsplit(files$file, "/")[1:4][[3]]][, Geom:=tstrsplit(files$file, "/")[1:4][[4]]][time_[s]<=12000]
I tried most of the suggestions above and they didn´t work. but I figured out that they can be split after the comma within []. Splitting at ][ doesn´t work.
mass <- files[, Veg:=tstrsplit(files$file, "/")[1:4][[1]]][,
Rain:=tstrsplit(files$file, "/")[1:4][[2]]][,
Roughness:=tstrsplit(files$file, "/")[1:4][[3]]][,
Geom:=tstrsplit(files$file, "/")[1:4][[4]]][`time_[s]`<=12000]
There is no coinvent way to do this because there is no operator in R to do string concatenation.
However, you can define a R Infix operator to do string concatenation:
`%+%` = function(x,y) return(paste0(x,y))
Then you can use it to concat strings, even break the code to multiple lines:
s = "a" %+%
"b" %+%
"c"
This will give you "abc".
This will keep the \n character, but you can also just wrap the quote in parentheses. Especially useful in RMarkdown.
t <- ("
this is a long
string
")
I do this all of the time. Use the paste0() function.
Rootdir = "/myhome/thisproject/part1/"
Subdir = "subdirectory1/subsubdir2/"
fullpath = paste0( Rootdir, Subdir )
fullpath
> fullpath
[1] "/myhome/thisproject/part1/subdirectory1/subsubdir2/"
I use knitr to have LaTeX pull numbers directly from R output, e.g., using \Sexpr{res$a[1]} to \Sexpr{res$a[5]}. Is there a way to automatically precede positive numbers with a plus sign? Sure, I could add plus signs to relevant numbers manually, but this seems to defeat the purpose of knitr.
Sorry it took me a while to get back to this. And it turned out to be easier than I thought. knitr doesn't appear to have its own options for controlling printing options. Instead, it relies on the options from your R session.
Now consider the following:
x <- 5.1234567899876543
x
[1] 5.123457
options()$digits
[1] 7
So the way the number is printed to the console is (partially) determined by options("digits"). Now, watch what happens when we apply the format function to x with all of the default arguments:
format(x)
[1] "5.123457"
We get back a character string that matches the representation when we simply printed x. Let's leverage this to our benefit:
with_plus <- function(x, ...)
{
if (x > 0)
{
sprintf(
fmt = "+ %s",
format(x, ...)
)
}
else
{
x
}
}
with_plus(x)
[1] "+ 5.123457"
Now you have a function that, under the default settings, will print numbers the same way they appear in the console but with a "+" prepended to positive numbers. Using format, you also get the flexibility to adjust individual values as needed.
Piston_Rings<-diameter[1:25,]
I want my quality control graph NOT to have the underscore in the object name.
At the moment there is an underscore (not a hyphen) in that object name. It is possible to construct objects whose names have spaces in them but in order to access them you will then always need to use backticks in order to get the interpreter to understand what you want:
> `Piston Rings` <- list(1,2)
> `Piston Rings`[[1]]
[1] 1
> `Piston Rings`[[2]]
[1] 2
The problem you incur is cluttering up your code, at least relative to obeying the usual conventions in R where a space is a token-ending marker to the parser. Hyphens (at least short-hyphens) are actually minus signs.
If on the other hand you only want to use a modified version of a name that contains an underscore as the title for a graph, then try something like this:
Piston_Rings <- list() # just for testing purposes so there will be an object.
plot( 1:10,10:1, main = sub("_", " ", quote(Piston_Rings)) )
#BondedDust's answer is correct, but (guessing, since you haven't been very specific) a simpler way to get what you want is just to specify xlab or ylab arguments to the plot() function. Let's say you have variables stuff (x) and Piston_Rings (y). If you just
plot(stuff,Piston_Rings)
then the plot will have "Piston_Rings" as the y-axis label. But if you
plot(stuff,Piston_Rings,ylab="Piston Rings")
you'll get the label you want. You can also include lots more information this way:
plot(stuff,Piston_Rings,
xlab="Important stuff (really)",
ylab="Piston Rings (number per segment)")
See ?plot.default for many more options.
I wonder if there is a way to split a call to a function in R over several lines, other then using commas or '+' which is not always applicable.
I am basically looking like Python's '\' escape.
For example, I want to display this line:
PromoterIslands$illumina_probes[bins_with_probes]-tapply(CGIP_to_Probe$subjectHits,CGIP_to_Probe$subjectHits,function(x) length(x))
as:
PromoterIslands$illumina_probes[bins_with_probes]
<-tapply(CGIP_to_Probe$subjectHits,CGIP_to_Probe$subjectHits,
function(x) length(x))]
Is there any way to do this?
Thanks in advance
You can just split commands on various lines, no special sign needed.
The command you wrote is almost OK, you just need to put the <- operator on the first line.
So for instance, this is valid R code, and will assign 13 to a
a <-
5 +
8
But this is not
a
<- 5 +
8
Note, however, that this is valid code
a <-
5
+ 8
But would assign 5 to a and print 8.
Assuming you're talking about source (as opposed to desiring to get something to print a particular way), you can break R code in any place that doesn't produce a syntactically complete statement. There is no special character that tells R that the statement isn't complete. In your case, one option is:
PromoterIslands$illumina_probes[bins_with_probes] <-
tapply(
CGIP_to_Probe$subjectHits,
CGIP_to_Probe$subjectHits,
function(x) length(x)
)
You have to leave the <- at the end of the first line, otherwise PromoterIslands$illumina_probes[bins_with_probes] is a syntactically complete statement that would get evaluated. Similarly, on the next line, you have to leave the ( on the same line as tapply otherwise tapply is a syntactically complete statement (returns the contents of the tapply function).
While this doesn't quite answer your question, hopefully you will find there are enough places you can break a line in R that the lack of the special command you are looking for isn't a problem.
I'm trying to make a legend in a ggplot2 plot that contains a minus sign as an exponent (with no other characters in the exponent). However, I can't figure out the plotmath syntax.
It seems like the following would work:
expr1 <- expression(paste("text", main[sub]^{-}))
ggplot(mpg, aes(x=cty, y=hwy, colour=drv)) + geom_point() +
scale_colour_discrete(labels=c(expr1, "b", "c"))
(And it does work if we say expr1 <- expression(paste("text", main[sub]^{super})). Is there an escape character or something for minus signs in plotmath?
You are almost certainly going to need to put quotes around that minus sign, because it would otherwise be expected to be an infix operator and as such require arguments before and after it. Add a small test case if that does not solve the problem.
Escaping does not work in plotmath. In particular you cannot use "\n" as an end-of-line/newline marker (as is documented in the help(plotmath) page.
This also succeeds:
expr1 <- expression(paste("text", main[sub]^{phantom()-phantom()}))
I had never before tried using phantom preceding and succeeding an infix operator, but it seems acceptable to interpreter. Plotmath expressions do get parsed and need to conform to R-parsing rules. See ?Syntax. As noted in comments, using "-" as a prefix operator to a single phantom() also succeeds because the minus sign can be used as either a unary-minus or a binary-minus:
expr1 <- expression(paste("text", main[sub]^{-phantom()}))
We could also have used an empty character value as the item after the prefix minus: {-""}