I'm trying to write a function equivalent to scales::dollar that adds a pound (£) symbol to the beginning of a figure. Since the scales code is so robust, I've used it as a framework and simply replaced the $ for the £.
A stripped-down function example:
pounds<-function(x) paste0("£",x)
When I run a CHECK I get the following:
Found the following file with non-ASCII characters:
pounds.R
Portable packages must use only ASCII characters in their R code,
except perhaps in comments.
Use \uxxxx escapes for other characters.
Looking through the Writing R extensions guide it doesn't give a lot of help (IMO) on how to resolve this issue. It mentions the \uxxxx and says it refers to Unicode characters.
Looking up unicode characters yields me the code £ but the guidance I can find for \uxxxx is minimal and relates to Java on W3schools.
My question is thus:
How do you implement the usage of non-unicode characters in R functions using the \uxxxx escapes and how does the usage affect the display of such characters after the function has been used?
For the \uxxxx escapes, you need to know the hexadecimal number of your character. You can determine it using charToRaw:
sprintf("%X", as.integer(charToRaw("£")))
[1] "A3"
Now you can use this to specify your non-ascii character. Both \u00A3 and £ represent the same character.
Another option is to use stringi::stri_escape_unicode:
library(stringi)
stringi::stri_escape_unicode("➛")
# "\\u279b"
This informs you that "\u279b" represents the character "➛".
Try this:
pounds<-function(x) paste0("\u00A3",x)
The stringi package can be useful is these situations:
library(stringi)
stri_escape_unicode("£")
#> [1] "\\u00a3"
Related
If we type in letters we get all lowercase letters from english alphabet. However, there are many more possible characters like ä, é and so on. And there are symbols like $ or (, too. I found this table of unicode characters which is exactly what I need. Of course I do not want to copy and paste hundreds of possible unicode characters in one vector.
What I've tried so far: The table gives the decimals for (some of) the unicode characters. For example, see the following small table:
Glyph Decimal Unicode Usage in R
! 33 U+0021 "\U0021"
So if type "\U0021" we get a !. Further, paste0("U", format(as.hexmode(33), width= 4, flag="0")) returns "U0021" which is quite close to what I need but adding \ results in an error:
paste0("\U", format(as.hexmode(33), width= 4, flag="0"))
Error: '\U' used without hex digits in character string starting ""\U"
I am stuck. And I am afraid even if I figure out how to transform numbers to characters usings as.hexmode() there is still the problem that there are not Decimals for all unicode characters (see table, Decimals end with 591).
Any idea how to generate a vector with all the unicode characters listed in the table linked?
(The question started with a real world problem but now I am mostly simply eager to know how to do this.)
There may be easier ways to do this, but here goes. The Unicode package contains everything you need.
First we can get a list of unicode scripts and the block ranges:
library(Unicode)
uranges <- u_scripts()
Check what we've got:
head(uranges, 3)
$Adlam
[1] U+1E900..U+1E943 U+1E944..U+1E94A U+1E94B U+1E950..U+1E959 U+1E95E..U+1E95F
$Ahom
[1] U+11700..U+1171A U+1171D..U+1171F U+11720..U+11721 U+11722..U+11725 U+11726 U+11727..U+1172B U+11730..U+11739 U+1173A..U+1173B U+1173C..U+1173E U+1173F
[11] U+11740..U+11746
$Anatolian_Hieroglyphs
[1] U+14400..U+14646
Next we can convert the ranges into their sequences.
expand_uranges <- lapply(uranges, as.u_char_seq)
To get a single vector of all characters we can unlist it. This won't be easy to work with so really it would be better to keep them as a list:
all_unicode_chars <- unlist(expand_uranges)
# The Wikipedia page linked states there are 144,697 characters
length(all_unicode_chars)
[1] 144762
So seems to be all of them and the page needs updating. They are stored as integers so to print them (assuming the glyph is supported) we can do, for example, printing Japanese katakana:
intToUtf8(expand_uranges$Katakana[[1]])
[1] "ァアィイゥウェエォオカガキギクグケゲコゴサザシジスズセゼソゾタダチヂッツヅテデトドナニヌネノハバパヒビピフブプヘベペホボポマミムメモャヤュユョヨラリルレロヮワヰヱヲンヴヵヶヷヸヹヺ"
I'm working with the following code:
Y_Columns <- c("Y.1.1")
paste('{"ImportId":"', Y_Columns, '"}', sep = "")
The paste function produces the following output:
"{\"ImportId\":\"Y.1.1\"}"
How do I get the paste function to omit the \? Such that, the output is:
"{"ImportId":"Y.1.1"}"
Thank you for your help.
Note: I did do a search on SO to see if there were any Q's that asked "what is an escape character in R". But I didn't review all the 160 answers, only the first 20.
This is one way of demonstrating what I wrote in my comment:
out <- paste('{"ImportId":"', Y_Columns, '"}', sep = "")
out
#[1] "{\"ImportId\":\"Y.1.1\"}"
?print
print(out,quote=FALSE)
#[1] {"ImportId":"Y.1.1"}
Both R and regex patterns use escape characters to allow special characters to be displayed in print output or input. (And sometimes regex patterns need to have doubled escapes.) R has a few characters that need to be "escaped" in certain situation. You illustrated one such situation: including double-quote character inside a result that will be printed with surrounding double-quotes. If you were intending to include any single quotes inside a character value that was delimited by single quotes at the time of creation, they would have needed to be escaped as well.
out2 <- '\'quoted\''
nchar(out2)
#[1] 8 ... note that neither the surround single-quotes nor the backslashes get counted
> out2
[1] "'quoted'" ... and the default output quote-char is a double-quote.
Here's a good Q&A to review:How to replace '+' using gsub() function in R
It has two answers, both useful: one shows how to double escape a special character and the other shows how to use teh fixed argument to get around that requirement.
And another potentially useful Q&A on the topic of handling Windows paths:
File path issues in R using Windows ("Hex digits in character string" error)
And some further useful reading suggestions: Look at the series of help pages that start with capital letters. (Since I can never remember which one has which nugget of essential information, I tried ?Syntax first and it has a "See Also" list of essential reading: Arithmetic, Comparison, Control, Extract, Logic, NumericConstants, Paren, Quotes, Reserved. and I then realized what I wanted to refer you to was most likely ?Quotes where all the R-specific escape sequence letters should be listed.
In Unicode, letters with accents can be represented in two ways: the accentuated letter itself, and the combination of the bare letter plus the accent. For example, é (+U00E9) and e´ (+U0065 +U0301) are usually displayed in the same way.
R renders the following (version 3.0.2, Mac OS 10.7.5):
> "\u00e9"
[1] "é"
> "\u0065\u0301"
[1] "é"
However, of course:
> "\u00e9" == "\u0065\u0301"
[1] FALSE
Is there a function in R which converts two-unicode-character-letters into their one-character form? In particular, here it would collapse "\u0065\u0301" into "\u00e9".
That would be extremely handy to process large quantities of strings. Plus, the one-character forms can easily be converted to other encodings via iconv -- at least for the usual Latin1 characters -- and is better handled by plot.
Thanks a lot in advance.
Ok, it appears that a package has been developed to enhance and simplify the string manipulation toolbox in R (finally!). It is called stringi and looks very promising. Its documentation is very well written, and in particular I find the pages about encodings and locales much more enlightening than some of the standard R documentation on the subject.
It has Unicode normalization functions, as I was looking for (here form C):
> stri_trans_nfc('\u00e9') == stri_trans_nfc('\u0065\u0301')
[1] TRUE
It also contains a smart comparison function which integrates these normalization questions and lessens the pain of having to think about them:
> stri_compare('\u00e9', '\u0065\u0301')
[1] 0
# i.e. equal ;
# otherwise it returns 1 or -1, i.e. greater or lesser, in the alphabetic order.
Thanks to the developers, Marek Gągolewski and Bartek Tartanus, and to Kurt Hornik for the info!
I want a character variable in R taking the value from, lets say "a", and adding " \%", to create a %-sign later in LaTeX.
Usually I'd do something like:
a <- 5
paste(a,"\%")
but this fails.
Error: '\%' is an unrecognized escape in character string starting "\%"
Any ideas? A workaround would be to define another command giving the %-sign in LaTeX, but I'd prefer a solution within R.
As many other languages, certain characters in strings have a different meaning when they're escaped. One example for that is \n, which means newline instead of n. When you write \%, R tries to interpret % as a special character and fails doing so. You might want to try to escape the backslash, so that it is just a backslash:
paste(a, "\\%")
You can read on escape sequences here.
You can also look at the latexTranslate function from the Hmisc package, which will escape special characters from strings to make them LaTeX-compatible :
R> latexTranslate("You want to give me 100$ ? I agree 100% !")
[1] "You want to give me 100\\$ ? I agree 100\\% !"
I am trying to read this file (3.8mb) using its fixed-width structure as described in the following link.
This command:
a <- read.fwf('~/ccsl.txt',c(2,30,6,2,30,8,10,11,6,8))
Produces an error:
line 37 did not have 10 elements
After replicating the issue with different values of the skip option, I figured that the lines causing the problem all contain the "#" symbol.
Is there any way to get around it?
As #jverzani already commented, this problem is probably the fact that the # sign often used as a character to signal a comment. Setting the comment.char input argument of read.fwf to something other than # could fix the problem. I'll leave my answer below as a more general case that you can use on any character that causes problems (e.g. the 's in the Dutch city name 's Gravenhage).
I've had this problem occur with other symbols. The approach I took was to simply replace the # by either nothing, or by a character which does not generate the error. In my case it was no problem to simply replace the character, but this might not be possible in your case.
So my approach would be to delete the symbol that generates the error, or replace by another character. This can be done using a text editor (find and replace), in an R script, or using some linux tools called grep and sed. If you want to do this in an R script, use scan or readLines to read the lines. Once the text is in memory, you can use sub to replace the character.
If you cannot replace the character, I would try the following approach: replace the character by a character that does not generate an error, read it into R using read.fwf, and finally replace the character by the # character.
Following up on the answer above: to get all characters to be read as literals, use both comment.char="" and quote="" (the latter takes care of #PaulHiemstra's problem with single-quotes in Dutch proper nouns) in the call to read.fwf (this is documented in ?read.table).