In scala, "here docs" is begin and end in 3 "
val str = """Hi,everyone"""
But what if the string contains the """? How to output Hi,"""everyone?
Since unicode escaping via \u0022 in multi-line string literals won’t help you, because they would be evaluated as the very same three quotes, your only chance is to concatenate like so:
"""Hi, """+"""""""""+"""everyone"""
The good thing is, that the scala compiler is smart enough to fix this and thus it will make one single string out of it when compiling.
At least, that’s what scala -print says.
object o {
val s = """Hi, """+"""""""""+"""everyone"""
val t = "Hi, \"\"\"everyone"
}
and using scala -print →
Main$$anon$1$o.this.s = "Hi, """everyone";
Main$$anon$1$o.this.t = "Hi, """everyone";
Note however, that you can’t input it that way. The format which scala -print outputs seems to be for internal usage only.
Still, there might be some easier, more straightforward way of doing this.
It's a totally hack that I posted on a similar question, but it works here too: use Scala's XML structures as an intermediate format.
val str = <a>Hi,"""everyone</a> text
This will give you a string with three double quotation marks.
you can't
scala heredocs are raw strings and don't use any escape codes
if you need tripple quotes in a string use string-concatenation add them
You can't using the triple quotes, as far as I know. In the spec, section 1.3.5, states:
A multi-line string literal is a sequence of characters enclosed in triple quotes
""" ... """. The sequence of characters is arbitrary, except that it may contain
three or more consuctive quote characters only at the very end. Characters must
not necessarily be printable; newlines or other control characters are also permitted.
Unicode escapes work as everywhere else, but none of the escape sequences in
(§1.3.6) is interpreted.
So if you want to output three quotes in a string, you can still use the single quote string with escaping:
scala> val s = "Hi, \"\"\"everyone"
s: java.lang.String = Hi, """everyone
Related
I'm facing a problem with string in MATLAB the default string is C:\Users\Root\Downloads\Path. I want to make this string with single quotes inside it like this 'C:\Users\Root\Downloads\Path\'. I try many times to escape the string with backslash like other programming languages but MATLAB didn't doing this i don't know how to fix this problem.
Code:
clear all
clc
s='C:\Users\Root\Downloads\Path';
str=fprintf('%s',s);
The trick is to use two quotes instead of one:
s='''C:\Users\Root\Downloads\Path''';
str=fprintf('%s',s)
'C:\Users\Root\Downloads\Path'
str =
30
Note that str will be the number 30, since fprintf returns the number of characters it prints, not the string itself! If you just want the string, then the first line is enough.
disp(s)
'C:\Users\Root\Downloads\Path'
Note that there is no data type "String" in MATLAB. You have an array of characters.
As part of a larger parser, I am writing a rule to match strings like the following using parboiled2:
Italiana Relè
I would like to use something simple like the following:
CharPredicate.Printable
But the parser is failing with an org.parboiled2.ParseError because of the unicode character at the end of the string.
Is there a simple option that I'm not aware of for matching printable unicode characters?
Take a look at https://github.com/sirthias/parboiled2/blob/master/parboiled-core/src/main/scala/org/parboiled2/CharPredicate.scala#L112 - it is very easy to do your own predicates, for instance:
val latinSupplementCharsPredicate = CharPredicate('\u00c0' to '\u00dc') ++ CharPredicate('\u00e0' to '\u00fd')
Please could anyone explain me why the following happens:
"Fancy string - Hor""ray"
# outputs correctly (only one double quote): Fancy string - Hor"ray
'Hor"ray'.Replace('"', '""')
# outputs correctly (two double quotes): Hor""ray
"Fancy string - $('Hor"ray'.Replace('"', '"'+'"'))"
#outputs correctly (two double quotes): Hor""ray
"Fancy string - $('Hor"ray'.Replace('"', '""'))"
# outputs INCORRECTLY (only one double quote): Fancy string - Hor"ray
In my opinion, developers would intuitively expect, that within "$(inline expressions)" Powershell would treat text as statements and won't interfere with the last argument of Replace('"', '""') converting it into '"' (unless the statement interpreter decides to do so).
Do I miss something here?
This appears to be a bug in how PowerShell parses expandable string literals.
From §2.3.5.2 on string literals in the PowerShell 3.0 Language Specification, the expandable-string-literal explicitly rejects the $( sequence so that sub-expression parsing will occur instead.
So it seems reasonable to expect $('""') to parse consistently, whether or not it happens to be embedded in a string literal. And clearly sub-expressions are parsed separately, since they support values that would be illegal on their own in an expandable string (e.g. you can write "$('"')" or "$('`""')", where " '"' " or " '`""' " would fail).
However, comparing the AST from [Management.Automation.Language.Parser]::ParseInput for both $('""') and "$('""')", we get two different results. Both have a final StringConstantExpressionAst element with an Extent of '""', but the Value for the stand-alone sub-expression is "" while the Value for the embedded sub-expression is ".
Its because the inline expression is evaluated and its string value is then placed in the string and evaluated.
#Breaking "Fancy string - $('Hor"ray'.Replace('"', '""'))" down
#This inline expression is evaluated first
$('Hor"ray'.Replace('"', '""'))
#giving
Hor""ray
#That value is then interpreted as part of the string
"Fancy string - Hor""ray"
#giving
Fancy string - Hor"ray
This is exactly what I would expect to see. The inline expression evaluated and its resulting value then being used.
Could this not be done by simply using things like below:
`'$($RemFiles[$i].FullName)`'
`"$($RemFiles[$i].FullName)`"
Use the backtick and either a single or double quote to then prevent powershell from using this as an open comment, thus putting the actual symbol in...
The above outputs:
'F:\portable\adobe'
or
"F:\portable\adobe"
I noticed that it seems you are telling it to literally add two double quotes rather than just using the backtick to force it. Therefore telling it to add nothing surely :S So could you change this to something like this:
"Fancy string - $('Hor"ray'.Replace('"', '`"`"'))"
Though that may make 3, as you have one present in Hor"ray anyway.
Just got to test it, was busy with something:
PS D:\> "Fancy string - $('Hor"ray'.Replace('"', '`"`"'))"
Fancy string - Hor""ray
Scroll down on the site below to find out about the backtick and how/where it can be used.
http://www.neolisk.com/techblog/powershell-specialcharactersandtokens
Coffeescript supports strings interpolation:
user = "world"
greeting = "Hello #{user}!"
Is it possible to use interpolation in regex just like in strings? E.g.
regex = /Hello #{user}/g
P.S. I know that I can use RegExp(greeting, 'g'), I just want a bit cleaner code.
Block Regular Expressions (Heregexes) support interpolation.
Block Regular Expressions
Similar to block strings and comments,
CoffeeScript supports block regexes — extended regular expressions
that ignore internal whitespace and can contain comments and
interpolation. Modeled after Perl's /x modifier, CoffeeScript's block
regexes are delimited by /// and go a long way towards making complex
regular expressions readable.
This coffeescript code:
name="hello"
test=///#{name}///
compiles to
var name, test;
name = "hello";
test = RegExp("" + name);
The Coffeescript docs contain the following blurb
String Interpolation, Block Strings, and Block Comments
Ruby-style string interpolation is included in CoffeeScript. Double-quoted strings allow for interpolated values, using #{ ... }, and single-quoted strings are literal.
Can someone explain what "single-quoted strings are literal" means here?
Does it just mean that there will be no interpretation? Is there a more javascripty meaning?
I ask because I was seeing a difference when using a single quoted string vs a double quoted as a object key.
name = "George"
"My Name: #{name}" ====> "My Name: George"
'My Name: #{name}' ====> "My Name: #{name}"
Literal in this case means that it is literally what you wrote in the string
For this reason (and a few others) I like to use a convention of double quotes when the string is natural language that is meaningful to an end user (for example an error message). And single quotes for symbols that are meaningful to the program (like property names, flags, module names, etc).
And no, that's not your fault, the word 'literal' has like 20 definitions in cs.