How text-replace property work in css? - css

I was taking a test in upwork. There I got the following question:
Consider the following code:
body{text-replace: "a" "b" "b" "c"}
What will be the output of the following string if the text replace style is implemented?
andy lives behind cafe
ndy lives behind cbfe
cndy lives cehind ccfe
andy lives behind cafe
andy lives cehind bafe
I couldn't find any reference for the text-replace property in css.

Wow! You've stumbled upon a property that was last in the 2007 GCPM specification and removed in the 2010 revision. And in an online test at that! Either the test you're taking is several years out of date, or whoever set it was just pulling from random old revisions of W3C specifications and treating them all as relevant (as users have been known to do here on Stack Overflow).
Because of how esoteric this is I'm going to just answer the question. Needless to say, this answer is provided for educational purposes only. There is no text-replace property in any current CSS specification, and there hasn't been for almost a decade (neither in css-content nor css-gcpm). Don't put it in your CSS and expect it to work. It won't. If you need to do text replacements in an HTML document, use JavaScript.
The answer is #2: "cndy lives cehind ccfe"
The exact CSS sample appears in the spec, linked above, and the example is described as follows (emphasis mine):
The two rules below yield the same result. In the first rule all ‘a’ characters are converted to ‘b’. Subsequently, all ‘b’ characters are converted to ‘c’. In the second rule, all ‘a’ and ‘b’ characters are converted directly to ‘c’.
body { text-replace: "a" "b" "b" "c" }
body { text-replace: "a" "c" "b" "c" }
So the processing order goes:
andy lives behind cafe
bndy lives behind cbfe
cndy lives cehind ccfe

Related

Forcing "ct" ligature for Google Web Fonts

I'm using the font IM Fell English for my project: https://fonts.google.com/specimen/IM+Fell+English?selection.family=IM+Fell+English
It has support for the "long s" ſ, and other common ligatures such as "ff", "fi", "ft", etc.
However, I can't seem to get "ct" ligature working, albeit you can see that the font does have the glyph: here 1) https://www.fontsquirrel.com/fonts/im-fell-english-pro and here 2) https://iginomarini.com/fell/the-revival-fonts/
I have tried font-variant-ligatures CSS property as directed here, but it does not work regardless of which value I set: https://developer.mozilla.org/en-US/docs/Web/CSS/font-variant-ligatures
My current compromise is to replace the "s" with "ſ" Unicode character, but as far as I know, there is no such Unicode character for the "ct" ligature (nor a joiner glyph) (as far as I could find!)
Additionally, to get the long ſ to work, I had to #import the font in such way:
#import url('https://fonts.googleapis.com/css?family=IM+Fell+English:400,400i&subset=all&text=+!%22%23$%25%26()*%2B,-.%2F0123456789:;%3C%3D%3E%3F#ABCDEFGHIJKLMNOPQRSTUVWXYZ%5B%5C%5Dabcdefghijklmnopqrstuvwxyz%7B%7D%C2%A2%C2%A3%C2%A5%C2%A9%C2%AE%C3%97%C3%B7%C5%BF%E2%80%98%E2%80%99%E2%80%9C%E2%80%9D%E2%82%AC');
The method which I obtained the value for the text parameter was that I inputted the long ſ into the preview field on the Google Font webpage for IM Fell English (the first link above), and then I watch which request my browser sent out and copied it.
As you can see below, I am much in need of re-creating this! (Notice the "ct" in "Octaves"; I've taken care of the long ſ in the titles, but not the paragraphs)
Recreation:
Original Source:
Edit: I've found a workaround.
I downloaded the IM Fell English font, then use Character Map (which is available under Windows 10), and search for the glyph and copied it (U+E004 Private Use). The trouble now is that I cannot search (using Ctrl F) for anything that contains the ligature! So, I cannot search for "Octaves" because it is now "Oaves".
I believe the original question in the title still stands. I don't want a workaround, I want to have the browser force the ligature, if that's possible.

Is it possible to have a set of option for a regex substring in R?

I have a dataframe that contains some cells with error messages as string. The strings come in the following forms:
ERROR-100_Data not found for ID "xxx"
ERROR-100_Data not found for id "xxx"
ERROR-101_Data not found for SUBID "yyy"
Data not found for ID "xxx"
Data not found for id "xxx"
I need to extract the number of the error (if it has one) and the GENERAL description, avoiding the specificity of the ID or SUBID. I have a function where I use the following regex expression:
sub(".*?ERROR-(.*?)for ID.*","\\1",df[,col1],sep="-")
This works only for the first case. Is there a way to obtain the following results using only one expression?
100_Data not found
100_Data not found
101_Data not found
Data not found
Data not found
We can use:
tsxt <- 'ERROR-100_Data not found for ID "xxx"'
gsub("\\sfor.*|ERROR-","",tsxt, perl=TRUE)
[1] "101_Data not found"
Or as suggested by #Jan anchor ERROR to make it more general:
gsub("\\sfor.*|^ERROR-","",tsxt, perl=TRUE)
You could use
^ERROR-|\sfor.+
which needs to be replaced by an empty string, see a demo on regex101.com.
Use this regex:
.*?(?:ERROR-)?(.*?)\s+for\s+(?:[A-Z]*)?ID
This makes sure that ERROR- part is optional, then captures everything before for ...ID is encountered (case-insensitively). The only capturing group contains the desired text, which can then be used directly without needing any substitution.
The first and the third groups in this regex are non-capture groups, i.e., they'll match their content but not capture it for further usage, thus leaving us with only one capture group (the middle one). This is done since the OP isn't interested in the data they refer to. Making them as capture groups would have meant three results, and the post-processing would have involved hard-coding the usage of second group only (the middle one), without ever having to deal with the other two.
Demo

Matching emails format using R

I was having an intro class at datacamp.com and ran into a problem.
Goal: find right emails using grep. "Right emails" defined by having an "#", end with ".edu").
Emails vector:
emails <- c("john.doe#ivyleague.edu", "education#world.gov", "dalai.lama#peace.org",
"invalid.edu", "quant#bigdatacollege.edu", "cookie.monster#sesame.tv")
I was thinking of
grep("#*\\.edu$",emails)
and it gave me
[1] 1 4 5
because I thought "*" matches "multiple characters". Later I found that it doesn't work like that.
Turned out the right code is
grep("#.*\\.edu$",emails)
I googled some documentation and only have a vague sense of how to get the correct answer. Can someone explain how exactly R match the right emails? Thanks a bunch!!
You've already been advised the using the asterisk quantifier wasn't giving you the specificity you needed, so use the "+" quantifier, which forces at least one such match. I decided to make the problem more complex by adding some where there were duplicated at-signs:
emails <- c("john.doe##ivyleague.edu", "education##world.gov", "dalai.lama#peace.org",
"invalid.edu", "quant#bigdatacollege.edu", "cookie.monster#sesame.tv")
grep( "^[^#]+#[^#]+\\.edu$", emails)
#[1] 5
That uses the regex character-class structure where items inside flankking square-brackets are taken as literals except when there is an initial up-caret ("^"), in which case it is the negation of the character class, i.e. in this case any character except "#". This will also exclude situations where the at-sign is the first character. Thanks to KonradRudolph who pointed out that adding "^" as the first character in the pattern (which signifies the point just before the first character of a potential match) would prevent allowing Items with an initial "##" from being matched.

Assigning and removing objects in a loop: eval(parse(paste(

I am looking to assign objects in a loop. I've read that some form of eval(parse( is what I need to perform this, but I'm running into errors listing invalid text or no such file or directory. Below is sample code of generally what I'm attempting to do:
x <- array(seq(1,18,by=1),dim=c(3,2,3))
for (i in 1:length(x[1,1,])) {
eval(parse(paste(letters[i],"<-mean(x[,,",i,"])",sep="")
}
And when I'm finished using these objects, I would like to remove them (the actual objects are very large and cause memory problems later on...)
for (i in 1:length(x[1,1,])) eval(parse(paste("rm(",letters[i],")",sep="")))
Both eval(parse(paste( portions of this script return errors for invalid text or no such file or directory. Am I missing something in using eval(parse(? Is there a easier/better way to assign objects in a loop?
That's a pretty disgusting and frustrating way to go about it. Use assign to assign and rm's list argument to remove objects.
> for (i in 1:length(x[1,1,])) {
+ assign(letters[i],mean(x[,,i]))
+ }
> ls()
[1] "a" "b" "c" "i" "x"
> a
[1] 3.5
> b
[1] 9.5
> c
[1] 15.5
> for (i in 1:length(x[1,1,])) {
+ rm(list=letters[i])
+ }
> ls()
[1] "i" "x"
>
Whenever you feel the need to use parse, remember fortune(106):
If the answer is parse() you should
usually rethink the question.
-- Thomas Lumley, R-help (February 2005)
Although it seems there are better ways to handle this, if you really did want to use the "eval(parse(paste(" approach, what you're missing is the text flag.
parse assumes that its first argument is a path to a file which it will then parse. In your case, you don't want it to go reading a file to parse, you want to directly pass it some text to parse. So, your code, rewritten (in what has been called disgusting form above) would be
letters=c('a','b','c')
x <- array(seq(1,18,by=1),dim=c(3,2,3))
for (i in 1:length(x[1,1,])) {
eval(parse(text=paste(letters[i],"<-mean(x[,,",i,"])",sep="")))
}
In addition to not specifying "text=" you're missing a few parentheses on the right side to close your parse and eval statements.
It sounds like your problem has been solved, but for people who reach this page who really do want to use eval(parse(paste, I wanted to clarify.
Very bad idea; you should never use eval or parse in R, unless you perfectly know what you are doing.
Variables can be created using:
name<-"x"
assign(name,3) #Eqiv to x<-3
And removed by:
name<-"x"
rm(list=name)
But in your case, it can be done with simple named vector:
apply(x,3,mean)->v;names(v)<-letters[1:length(v)]
v
v["b"]
#Some operations on v
rm(v)
It is best to avoid using either eval(paste( or assign in this case. Doing either creates many global variables that just cause additional headaches later on.
The best approach is to use existing data structures to store your objects, lists are the most general for these types of cases.
Then you can use the [ls]apply functions to do things with the different elements, usually much quicker than looping through global variables. If you want to save all the objects created, you have just one list to save/load. When it comes time to delete them, you just delete 1 single object and everything is gone (no looping). You can name the elements of the list to refer to them by name later on, or by index.

Insert unicode strings into CleverCSS

How can one insert a Unicode string CSS into CleverCSS?
In particular, how could one produce the following CSS using CleverCSS:
li:after {
content: "\00BB \0020";
}
I've figured out CleverCSS's parsing rules, but suffice that the permutations I've thought sensible have failed, for example:
li:
content: "\\00BB \\0020" // becomes content: 'BB 0'
EDIT: My other examples and the rest of my post weren't saved. Suffice to say that I had a longer list of examples that's missing.
I'd be grateful for any thoughts and input.
Brian
EDIT: I noted that inserting the unicode was one of the problems (once you start uploading CSS with utf-8 encoding it's fine). The wrapping of quote characters is another, which I solved that with something crazy likeso:
content: "'".string() + " ".string() ».string() + "'".string()
Hope that helps someone else.
This may be silly, but why still bother with escape sequences when you can just type/paste the actual characters? "A CSS style sheet is a sequence of characters from the Universal Character Set".
That is a lot easier on the eye, and is especially useful when maintaining existing code.
Or is CleverCSS not Unicode-enabled?
In looking at the code (CleverCSS 0.1) it would appear that the partial regular expression _r_string (defined on line 414) is where you would need to start. This is used to define several other REs, including _string_re which is used in the parsing rules (line 1374). This leads us to process_string() (line 1359) which looks like it was meant to accept Unicode.
Unfortunately, hand-built parsers tend to get a bit strange and the code is not exactly swimming in comments. If you really need to do this, I would focus on process_string() and put a bunch of before/after print statements in there and see if you can understand the goes-intos and goes-outofs.
You might also try bribing the original author with beer or ??? Good luck.

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