trackLbl2.text = #""Nonstop Bollywood Music"";
I try this but not working. How to text with double quotes.
Try this:
trackLbl2.text = #"\"Nonstop Bollywood Music\"";
You have to put \ before any special character to print it out.
The user before me provided a good answer, but I would like to elaborate on your problem a little bit. It's a good thing to know.
In most (all?) programming languages, certain characters usually serve a special function - single quotes, double quotes, backslashes, and the likes. If you want to include those inside a string, the common practice is to "escape" them, or use escape characters. Escape characters are special character combinations that get replaced with the actual character you want to see inside the string; they usually start with a forward slash (\)*.
Here is a list of common escape characters used in Objective C (source: Wikipedia)
\a - Sound alert
\b - Backspace
\f - Form feed
\n - New line
\r - Carriage return
\t - Horizontal tab
\v - Vertical tab
\ - Backslash
\" - Double quote (used when placing a double quote into a string declaration)
\' - Single quote (used when placing a double quote into a string declaration)
Fun fact: I actually had to escape that forward slash in there by typing "\\".
Try this
trackLbl2.text = #"\"Nonstop Bollywood Music\"";
You have to put \ before any special character to print it out.
Related
I have input that people will probably say "that's not really CSV", but I still have to parse it. (using Papa Parse)
comma is the delimiter. backslash is the escape. comma, double quote, backslash, r and n (to denote newlines) can all be escaped. There is no "quoting" of strings.
so... I see data like:
this is one\, field,1/2\" bolt,this is text with \\ and a new line \r\n embedded
and I want:
[0] this is one\, field
[1] 1/2\" bolt
[2] this is text with \\ and a new line \r\n embedded
but I'm getting
[0] this is one\
[1] field
[2] 1/2\" bolt
...
I can deal with the other \x things in post processing... I'd just like to get it to handle \, correctly.
I've tried the obvious values of quoteChar and escapeChar with no luck.
oh... and the Donate link is broken on https://www.papaparse.com/ if Matt Holt is listening.
const parsed = window.Papa.parse(csvText, {
escapeChar: '\\',
});
Seems like default escape character is ", but it can be overidden in the paramters.
Upd. though now that I look at it, it does not seem to work with your case. It only did fix an issue I had of 2.5\","Shell being considered single value because " was interpreted as escape character for ,.
I'm starting to get a feeling that the only way to escape coma is to enclose the field in the quotes.
Hope someone will post the right answer eventually...
I have tried to print it but it just by passes because it's an escaped character.
e.g output should be as follows.
\correct
For that and also future reference:
\0 – Null character (that is a zero after the slash)
\\ – Backslash itself. Since the backslash is used to escape other characters, it needs a special escape to actually print itself.
\t – Horizontal tab
\n – Line Feed
\r – Carriage Return
\” – Double quote. Since the quotes denote a String literal, this is necessary if you actually want to print one.
\’ – Single Quote. Similar reason to above.
Use the following code for Swift 5, Xcode 10.2
let myText = #"This is a Backslash: \"#
print(myText)
Output:
This is a Backslash: \
Now not required to add a double slash to use a single slash in swift 5, even now required slash before some character, for example, single quote, double quote etc.
See this post for latest update about swift 5
https://www.hackingwithswift.com/articles/126/whats-new-in-swift-5-0
var s1: String = "I love my "
let s2: String = "country"
s1 += "\"\(s2)\""
print(s1)
It will print I love my "country"
The backslash character \ acts as an escape character when used in a string. This means you can use, for example, double quotes, in a string by pre-pending them with \. The same also applies for the backslash character itself, which is to say that println("\\") will result in just \ being printed.
The following example prints "SAME":
if (q/\\a/ eq q/\a/) {
print "SAME\n";
}
else {
print "DIFFERENT\n";
}
I understand this is consistent with the documentation. But I think this behavior is undesirable. Is there a need to escape a backlash lilteral in single-quoted string? If I wanted 2 backlashes, I'd need to specify 4; this does not seem convenient.
Shouldn't Perl detect whether a backslash serves as an escape character or not? For instance, when a backslash does not precede a delimiter, it should be treated as a literal; and if that were the case, I wouldn't need 3 backslashes to express two, e.g.,
q<a\\b>
instead of
q<a\\\b>.
Is there a need to escape a backlash in single-quoted string?
Yes, if the backslash is followed by another backslash, or is the last character in the string:
$ perl -e'print q/C:\/'
Can't find string terminator "/" anywhere before EOF at -e line 1.
$ perl -e'print q/C:\\/'
C:\
This makes it possible to include any character in a single-quoted string, including the delimiter and the escape character.
If I wanted 2 backlashes, I'd need to specify 4; this does not seem convenient.
Actually, you only need three (because the second backslash isn't followed by another backslash). But as an alternative, if your string contains a lot of backslashes you can use a single-quoted heredoc, which requires no escaping:
my $path = <<'END';
C:\a\very\long\path
END
chomp $path;
print $path; # C:\a\very\long\path
Note that the heredoc adds a newline to the end, which you can remove with chomp.
In single-quoted string literals,
A backslash represents a backslash unless followed by the delimiter or another backslash, in which case the delimiter or backslash is interpolated.
In other words,
You must escape delimiters.
You must escape \ that are followed by \ or the delimiter.
You may escape \ that aren't followed by \ or the delimiter.
So,
q/\// ⇒ /
q/\\\\a/ ⇒ \\a
q/\\\a/ ⇒ \\a
q/\\a/ ⇒ \a
q/\a/ ⇒ \a
Is there a need to escape a backlash in single-quoted string?
Yes, if it's followed by another backslash or the delimiter.
If I wanted 2 backlashes, I'd need to specify 4
Three would suffice.
this does not seem convenient.
It's more convenient than double-quoted strings, where backslashes must always be escaped. Single-quoted string require the minimum amount of escaping possible without losing the ability to produce the delimiter.
I am trying to write a sed script to convert LaTeX coded tables into tab delimited tables.
To do this I need to convert & into \t and strip out anything that is preceded by \.
This is what I have so far:
s/&/\t/g
s/\*/" "/g
The first line works as intended. In the second line I try to replace \ followed by anything with a space but it doesn't alter the lines with \ in them.
Any suggestions are appreciated. Also, can you briefly explain what suggested scripts "say"? I am new to sed and that really helps with the learning process!
Thanks
Assuming you're running this as a sed script, and not directly on the command line:
s/\\.*/ /g
Explanation:
\\ - double backslash to match a literal backslash (a single \ is interpreted as "escape the following character", followed by a .* (. - match any single character, * - arbitrarily many times).
You need to escape the backslash as it is a special character.
If you want to denote "any character" you need to use . (a period)
the second expression should be:
s/\\.//g
I hope I understood your intention and you want to strip the character after the backslash,
if you want to delete all the characters in the line after the backslash add a star (*)
after the period.
I want to replace something with a path like C:\foo, so I:
s/hello/c:\foo
But that is invalid.
Do I need to escape some chars?
Two problems that I can see.
Your first problem is that your s/// replacement is not terminated:
s/hello/c:\foo # fatal syntax error: "Substitution replacement not terminated"
s/hello/c:\foo/ # syntactically okay
s!hello!c:\foo! # also okay, and more readable with backslashes (IMHO)
Your second problem, the one you asked about, is that the \f is taken as a form feed escape sequence (ASCII 0x0C), just as it would be in double quotes, which is not what you want.
You may either escape the backslash, or let variable interpolation "hide" the problem:
s!hello!c:\\foo! # This will do what you want. Note double backslash.
my $replacement = 'c:\foo' # N.B.: Using single quotes here, not double quotes
s!hello!$replacement!; # This also works
Take a look at the treatment of Quote and Quote-like Operators in perlop for more information.
If I understand what you're asking, then this might be something like what you're after:
$path = "hello/there";
$path =~ s/hello/c:\\foo/;
print "$path\n";
To answer your question, yes you do need to double the backslash because \f is an escape sequence for "form feed" in a Perl string.
The problem is that you are not escaping special characters:
s/hello/c:\\foo/;
would solve your problem. \ is a special character so you need to escape it. {}[]()^$.|*+?\ are meta (special) characterss which you need to escape.
Additional reference: http://perldoc.perl.org/perlretut.html