ruby .split('\n') not splitting on new line - ruby

Why does this string not split on each "\n"? (RUBY)
"ADVERTISING [7310]\n\t\tIRS NUMBER:\t\t\t\t061340408\n\t\tSTATE OF INCORPORATION:\t\t\tDE\n\t\tFISCAL YEAR END:\t\t\t0331\n\n\tFILING VALUES:\n\t\tFORM TYPE:\t\t10-Q\n\t\tSEC ACT:\t\t1934 Act\n\t".split('\n')
>> ["ADVERTISING [7310]\n\t\tIRS NUMBER:\t\t\t\t061340408\n\t\tSTATE OF INCORPORATION:\t\t\tDE\n\t\tFISCAL YEAR END:\t\t\t0331\n\n\tFILING VALUES:\n\t\tFORM TYPE:\t\t10-Q\n\t\tSEC ACT:\t\t1934 Act\n\t"]

You need .split("\n"). String interpolation is needed to properly interpret the new line, and double quotes are one way to do that.

In Ruby single quotes around a string means that escape characters are not interpreted. Unlike in C, where single quotes denote a single character. In this case '\n' is actually equivalent to "\\n".
So if you want to split on \n you need to change your code to use double quotes.
.split("\n")

Ruby has the methods String#each_line and String#lines
returns an enum:
http://www.ruby-doc.org/core-1.9.3/String.html#method-i-each_line
returns an array:
http://www.ruby-doc.org/core-2.1.2/String.html#method-i-lines
I didn't test it against your scenario but I bet it will work better than manually choosing the newline chars.

Or a regular expression
.split(/\n/)

You can't use single quotes for this:
"ADVERTISING [7310]\n\t\tIRS NUMBER:\t\t\t\t061340408\n\t\tSTATE OF INCORPORATION:\t\t\tDE\n\t\tFISCAL YEAR END:\t\t\t0331\n\n\tFILING VALUES:\n\t\tFORM TYPE:\t\t10-Q\n\t\tSEC ACT:\t\t1934 Act\n\t".split("\n")

Related

split string by spaces properly accounting for quotes and backslashes (ruby)

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(/(?:"(?:\\.|[^"])*"|[^" ])+/)

ruby regex about escape a escape

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:
^"(\\\\|\\"|[^"])*"$

BASH: Dollar sign substitution after a hash?

I am writing a script that deals with hex color values and I want to substitute in a user provided variable after a hash mark like so:
HEX=$1
COLOR='#$HEX'
But this fails as I believe it is interpreting the hash as a comment? How do I escape the hash so that I can have a variable which contains a string with a hash in it?
That fails because you're using single quotes. There's no variable substitution inside single quotes. Instead, use double quoted:
COLOR="#$HEX"
Single quotes block dollar interpolation. Double ones don't, so this should work:
COLOR="#$HEX"

How to make Ruby ignore backslash in strings?

Is there some way in Ruby that I can avoid having to put double-backslash in Ruby strings (like what can be done in C#):
For example, in C# was can prefix a string with # and then the backslash in the string does not need to be escaped:
#"C:\Windows, C:\ABC"
Without # we would need to escape the backslash:
"C:\\Windows, C:\\ABC"
Is there something similar in Ruby?
Use single quotes
my_string = 'C:\Windows'
See more in the Strings section here
You can also use %q and backslashes will be automatically escaped for you:
%q{C:\Windows} => "C:\\Windows"

Ruby - Making a newline within usage of gsub

I'm a bit stuck on this issue. I'm trying to make a newline using '\n'. I'm opening a file, then replacing the text, then writing it back as an html file:
replace = text.gsub(/aaa/, 'aaa\nbbb')
But this results in:
aaa\nbbb
I'm trying to make do:
aaa
bbb
In single-quoted strings a backslash is just a backslash (except if it precedes another backslash or a quote). Use double quotes: "aaa\nbbb" .
You'll want to read:Backslashes in Single quoted strings vs. Double quoted strings in Ruby?.

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