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/"
Related
I have a df = desc with a variable "value" that holds long text and would like to remove every word in that variable that ends with ".htm" . I looked for a long time around here and regex expressions and cannot find a solution.
Can anyone help? Thank you so much!
I tried things like:
library(stringr)
desc <- str_replace_all(desc$value, "\*.htm*$", "")
But I get:
Error: '\*' is an unrecognized escape in character string starting ""\*"
This regex:
Will Catch all that ends with .htm
Will not catch instances with .html
Is not dependent on being in the beginning / end of a string.
strings <- c("random text shouldbematched.htm notremoved.html matched.htm random stuff")
gsub("\\w+\\.htm\\b", "", strings)
Output:
[1] "random text notremoved.html random stuff"
I am not sure what exactly you would like to accomplish, but I guess one of those is what you are looking for:
words <- c("apple", "test.htm", "friend.html", "remove.htm")
# just replace the ".htm" from every string
str_replace_all(words, ".htm", "")
# exclude all words that contains .htm anywhere
words[!grepl(pattern = ".htm", words)]
# exlude all words that END with .htm
words[substr(words, nchar(words)-3, nchar(words)) != ".htm"]
I am not sure if you can use * to tell R to consider any value inside a string, so I would first remove it. Also, in your code you are setting a change in your variable "value" to replace the entire df.
So I would suggest the following:
desc$value <- str_replace(desc$value, ".htm", "")
By doing so, you are telling R to remove all .htm that you have in the desc$value variable alone. I hope it works!
Let's assume you have, as you say, a variable "value" that holds long text and you want to remove every word that ends in .html. Based on these assumptions you can use str_remove all:
The main point here is to wrap the pattern into word boundary markers \\b:
library(stringr)
str_remove_all(value, "\\b\\w+\\.html\\b")
[1] "apple and test2.html01" "the word must etc. and as well" "we want to remove .htm"
Data:
value <- c("apple test.html and test2.html01",
"the word friend.html must etc. and x.html as well",
"we want to remove .htm")
To achieve what you want just do:
desc$value <- str_replace(desc$value, ".*\\.htm$", "")
You are trying to escape the star and it is useless. You get an error because \* does not exist in R strings. You just have \n, \t etc...
\. does not exist either in R strings. But \\ exists and it produces a single \ in the resulting string used for the regular expression. Therefore, when you escape something in a R regexp you have to escape it twice:
In my regexp: .* means any chars and \\. means a real dot. I have to escape it twice because \ needs to be escape first from the R string.
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/"
This is a silly question, but I can't seem to find a solution in R online. I am trying to remove an isolated number from a long string. For example, I would like to remove the number 27198 from the sentence below.
x <- "hello3 my name 27198 is 5joey"
I tried the following:
gsub("[0-9]","",x)
Which results in:
"hello my name is joey"
But I want:
"hello3 my name is 5joey"
This seems really simple, but I am not well versed with regular expressions. Thanks for your help!
We can specify word boundary (\\b) at the end of one or more digits ([0-9]+)
gsub("\\b[0-9]+\\b", "", x)
#[1] "hello3 my name is 5joey"
is it possible to indent output in R?
e.g.
cat("text1\n")
indent.switch(indent=4)
cat("random text\n")
print("another random text")
indent.switch(indent=0)
cat("text2\n")
resulting in
text1
random text
another random text
text2
I searched for this a few months ago, found nothing and am now searching again.
My current idea is to "overwrite" (I forgot the special term) the functions cat and/or print with an additional argument like:
cat("random text", indent=4)
Only I'm stuck with this and I dont like this procedure very much.
Any ideas?
Edit:
I should be more particular, nevertheless thank you for the \t (omg, i totally forgot this -.-) and that I can format it inside cat.
The given solutions work, but only solve my second-choice-path.
A switch as shown in my first codeexample does not exist I suppose?
My problem is that I have parts of a bigger program which have multiple subscripts, and the output of each subscript should be indented. This is absolutely possible with the "\t" or just blanks inside cat() but has to be done in every command, which I dont like very much.
Solution
I used Chris C's code and extended it in a very easy way. (Thank you very much Chris!)
define.catt <- function(ntab = NULL, nspace=NULL){
catt <- function(input = NULL){
if(!is.null(ntab)) cat(paste0(paste(rep("\t", ntab), collapse = ""), input))
if(!is.null(nspace)) cat(paste0(paste(rep(" ", nspace), collapse = ""), input))
if(is.null(ntab) && is.null(nspace)) cat(input)
}
return(catt)
}
The same way you used \n to print a newline, you can use \t to print a tab.
E.g.
cat("Parent level \n \t Child level \n \t \t Double Child \n \t Child \n Parent level")
Evaluates to
Parent level
Child level
Double Child
Child
Parent level
As an alternative, you can create a derivative of cat called catt and alter options depending on the script. For example.
define.catt <- function(ntab = NULL){
catt <- function(input = NULL){
cat(paste0(paste(rep("\t", ntab), collapse = ""), input))
}
return(catt)
}
You would then set catt with however many tabs you wanted by
catt <- define.catt(ntab = 1)
catt("hi")
hi
catt <- define.catt(ntab = 2)
catt("hi")
hi
And just use catt() instead of cat().
You may consider the very versatile function capture.output(...), which evaluates the '...' list of expressions provided as main input arguments, and stores the text output (as if it would be displayed in the console) into a character vector instead. Then, you simply have to modify the strings as desired: here you want to add some leading spaces to each string. Finally, you write the strings to the console.
These can be done all in one line of nested calls. For example:
writeLines(paste(" ", capture.output(print(head(iris))), sep=""))
I therefore recommend you all to read the help of the capture.output function, and then try to use it for various purposes. Indeed, since the main input has the usual flexibility of the '...' list-like structure, you are free to include, for instance, a call to one home-made function, and thus do almost anything. As for indentation, that is simply done with paste function, once the former has done its magic.
I am using the following code for finding number of occurrences of a word memory in a file and I am getting the wrong result. Can you please help me to know what I am missing?
NOTE1: The question is looking for exact occurrence of word "memory"!
NOTE2: What I have realized they are exactly looking for "memory" and even something like "memory," is not accepted! That was the part which has brought up the confusion I guess. I tried it for word "action" and the correct answer is 7! You can try as well.
#names=scan("hamlet.txt", what=character())
names <- scan('http://pastebin.com/raw.php?i=kC9aRvfB', what=character())
Read 28230 items
> length(grep("memory",names))
[1] 9
Here's the file
The problem is really Shakespeare's use of punctuation. There are a lot of apostrophes (') in the text. When the R function scan encounters an apostrophe it assumes it is the start of a quoted string and reads all characters up until the next apostrophe into a single entry of your names array. One of these long entries happens to include two instances of the word "memory" and so reduces the total number of matches by one.
You can fix the problem by telling scan to regard all quotation marks as normal characters and not treat them specially:
names <- scan('http://pastebin.com/raw.php?i=kC9aRvfB', what=character(), quote=NULL )
Be careful when using the R implementation of grep. It does not behave in exactly the same way as the usual GNU/Linux program. In particular, the way you have used it here WILL find the number of matching words and not just the total number of matching lines as some people have suggested.
As pointed by #andrew, my previous answer would give wrong results if a word repeats on the same line. Based on other answers/comments, this one seems ok:
names = scan('http://pastebin.com/raw.php?i=kC9aRvfB', what=character(), quote=NULL )
idxs = grep("memory", names, ignore.case = TRUE)
length(idxs)
# [1] 10