puts 'I am 6\'2" tall'
the output is I am 6'2" tall
But in irb
if i types this string 'I am 6\'2" tall' without puts
i got like "I am 6'2\" tall"
Note the position of escape character in the output
Why the position of escape character got changed?
You got different types of quote characters escaped within different types of quotes.
Within single quotes, single quotes need to be escaped to be distinguished from the end of the string, but double quotes need not.
Within double quotes, single quotes need not be escaped, but double quotes need to be.
Because in IRB 'I am 6\'2" tall'.inspect is happening, which is same as puts 'I am 6\'2" tall'
Related
I want to escape all markdown characters with a backslash \.
I've tried
"testing _the thing".gsub /(\*|_|`)/, '\\\1'
And the result is:
testing \\_the thing
With only 2 \\
"testing _the thing".gsub /(\*|_|`)/, '\\1'
=> "testing _the thing"
The output I would like is:
=> "testing \_the thing"
I've tried many things without luck.
You're getting the right output. In inspect mode you'll see this:
"\\_"
That means "literal-backslash underscore". Remember that inside double-quoted strings the backslash is used for special characters and sequences like \t for tab or \n for newline. A backslash must be escaped if you want an actual backslash.
Try this:
puts "\\_"
You'll see just \_ like you want.
If you do this:
"\_"
That's "literal-underscore", which of course is just an underscore. The backslash ends up disappearing since it's redundant.
I want to split a string (insecure foreign line, like exim_mainlog line) by spaces, but not by spaces that are inside of double quotes, and ignore if the quote is escaped by a backslash like \", and ignore the backslash if it is just escaped like \\. Without slow parsing the string manually with FSM.
Example line:
U=mailnull T="test \"quote\" and wild blackslash\\" P=esmtps
Should be split into:
["U=mailnull", "T=\"test \\\"quote\\\" and wild blackslash\\\"", "P=esmtps"]
(Btw, I think ruby should had method for such split.., sigh).
I think I found simple enough solution: input.scan(/(?:"(?:\\.|[^"])*"|[^" ])+/)
Hi I need to create string like this:
drawtext="fontfile=/Users/stpn/Documents/Video_Experiments/fonts/Trebuchet_MS.ttf:text='content':fontsize=100:fontcolor=red:y=h/2"
I want to do something like
str = Q%[drawtext="fontfile=/Users/stpn/Documents/Video_Experiments/fonts/Trebuchet_MS.ttf:text='content':fontsize=100:fontcolor=red:y=h/2"]
I am getting this:
=> "drawtext=\"fontfile=/Users/stpn/Documents/Video_Experiments/fonts/Trebuchet_MS.ttf:text='content':fontsize=100:fontcolor=red:y=h/2\""
The escape characters after equals sign in drawtext=" is what I want to get rid of.. How to achieve that?
The string is to be used in a command line args.
Like many languages, Ruby needs a way of delimiting a quoted quote, and the enclosing quotes.
What you're seeing is the escape character which is a way of saying literal quote instead of syntactic quote:
foo = 'test="test"'
# => "test=\"test\""
The escape character is only there because double-quotes are used by default when inspecting a string. It's stored internally as a single character, of course. You may also see these in other circumstances such as a CR+LF delimited file line:
"example_line\r\n"
The \r and \n here correspond with carriage-return and line-feed characters. There's several of these characters defined in ANSI C that have carried over into many languages including Ruby and JavaScript.
When you output a string those escape characters are not displayed:
puts foo
test="test"
I am trying to write a regex in Ruby to test a string such as:
"GET \"anything/here.txt\""
the point is, everything can be in the outer double quote, but all double quotes in the outer double quotes must be escaped by back slash(otherwise it doesnt match). So for example
"GET "anything/here.txt""
this will not be a proper line.
I tried many ways to write the regex but doest work. can anyone help me with this? thank you
You can use positive lookbehind:
/\A"((?<=\\)"|[^"])*"\z/
This does exactly what you asked for: "if a double quote appears inside the outer double quotes without a backslash prefixed, it doesn't match."
Some comments:
\A,\z: These match only at the beginning and end of the string. So the pattern has to match against the whole string, not a part of it.
(?<=): This is the syntax for positive lookbehind; it asserts that a pattern must match directly before the current position. So (?<=\\)" matches "a double quote which is preceded by a backslash".
[^"]: This matches "any character which is not a backslash".
One point about this regex, is that it will match an inner double quote which is preceded by two backslashes. If that is a problem, post a comment and I'll fix it.
If your version of Ruby doesn't have lookbehind, you could do something like:
/\A"(\\.|[^"\\])*"\z/
Note that unlike the first regexp, this one does not count a double backslash as escaping a quote (rather, the first backslash escapes the second one), so "\\"" will not match.
This works:
/"(?<method>[A-Z]*)\s*\\\"(?<file>[^\\"]*)\\""/
See it on Rubular.
Edit:
"(?<method>[A-Z]*)\s(?<content>(\\\"|[a-z\/\.]*)*)"
See it here.
Edit 2: without (? ...) sequence (for Ruby 1.8.6):
"([A-Z]*)\s((\\\"|[a-z\/\.]*)*)"
Rubular here.
Tested this on Rubular successfully:
\"GET \\\".*\\\"\"
Breakdown:
\" - Escape the " for the regex string, meaning the literal character "
GET - Assuming you just want GET than this is explicit
\\" - Escape \ and " to get the literal string \"
.* - 0 or more of any character other than \n
\\"\" - Escapes for the literal \""
I'm not sure a regex is really your best tool here, but if you insist on using one, I recommend thinking of the string as a sequence of tokens: a quote, then a series of things that are either \\, \" or anything that isn't a quote, then a closing quote at the end. So this:
^"(\\\\|\\"|[^"])*"$
I am currently using Watir with Firefox and it seems that when I try to set a field with the following text:
##$QWER7890uiop
The command I am using is the following:
text_field(:name, "password").value=("!##$QWER7890uiop)
I've also tried this:
text_field(:name, "password").set "!##$QWER7890uiop)
Only the first 2 characters get entered. Is there something I can do to by pass this feature?
You need to escape the string using single quotes '.
text_field(:name, "password").value='"!##$QWER7890uiop'
Many characters are substituted inside double quotes.
Escape sequences like \n, \t, \s, etc are replaced by their equivalent character(s). See here for full list.
#{} where anything the braces is interpreted as a ruby expression.
#$something where $something is interpreted as a ruby global variable. That's the problem with your quote above, beside not being terminated.
%s is interpreted as an ERB template expression (it is interpolated).
For instance:
puts "%s hours later" % 'Five'
results in
"Five hours later".