I have some strings that look like any of these:
/challenges/:challenge_id/submissions/:id
/challenges/:challenge_id/submissions
/api/v1/submissions/:id
/submissions
The strings starting with ':' and ended by a '/' or a blank line are Rails route params. ie: 'challenge_id' and ':id'
I'd like to do 2 things with this string
extract the route param variables into a ruby array for later use
replace those param variables by '1'
So output for the first example:
arr = [':challenge_id',':id']
new string = '/challenges/1/submissions/1'
I've tried this, but it is matching everything
/[:[a-z*]]/
I'm testing in http://rubular.com/ as I need this to run in Ruby code.
arr = []
"/challenges/:challenge_id/submissions/:id".gsub(/:[^\/]+/){|s| arr.push(s); "1"}
# => "/challenges/1/submissions/1"
arr
# => [":challenge_id", ":id"]
If you want to match params that may have capital letters in them, then you can use \w shorthand:
:\w+
This will match all params including the ones with capital letters.
# For example:
/challenges/:Challenge_id/submissions/:ID
Ruby code:
string = "/challenges/:challenge_id/submissions/:id"
# To get a matching params array
string.scan(/:\w+/) # => [":challenge_id", ":id"]
# To replace them with "1"s
string.gsub(/:\w+/, '1') # => "/challenges/1/submissions/1"
The regex should be this:
(:[a-z]*)
() is for the capture group.
"*" should be outside the character class.
To improve your current regex, you could do this:
(\/:[a-z]+)
Add a forward slashes "/", so not to match ":" in the middle of the param variables and change the "*" operator to "+", so not to match ":" alone.
Related
I'm trying to move files to other directories with FileUtils.mv. I'm trying to define a variable called name_convention, which is a mix of strings, other variables and I also want to include a regexp, where I'm failing. My code so far:
#these are my other variables already declared from an array
season = array[11..13]
episode = array[15..17]
#and this is my 'name_convention' variable
name_convention = "friends" + season + episode + "bluray.mkv"
Up to here, everything is working fine. Except that between friends and season, there can be either a . or a _. For example:
friends_s01e01_bluray.mkv
friends.s01e01.bluray.mkv
I tried to use a regexp, like /(\.|-)/, but I got the error: no implicit conversion of regex into string ruby
How can I provide the two options to my name_convention variable, so that it can be applied to both filenames?
You're trying to interpolate a regex into a string, but you need to do the opposite - interpolate the strings into the regex:
season = "s01"
episode = "e01"
regex = /friends[\._]#{Regexp.escape(season)}#{Regexp.escape(episode)}.bluray.mkv/
regex.match "friends_s01e01_bluray.mkv"
# => MatchData
regex.match "friends.s01e01_bluray.mkv"
# => MatchData
regex.match "friends-s01e01_bluray.mkv"
# => nil
For this particular example (s01 and e01) you don't need the Regexp.escape but it's a good idea to include it just in case.
If you're looking for a quick and dirty sNNeNN parser, try this:
def parse_episode(str)
m = str.match(/\A(.*?)[\-\_\.]?(s\d+)(e\d+)[\-\_\.]?(.*)\z/i)
# If matched, strip out the first entry which is the complete match
m&.to_a&.drop(1)
end
Where this produces results like:
parse_episode('snowpiercer-s01e01-stream')
# => ["snowpiercer", "s01", "e01", "stream"]
parse_episode('s01')
# => nil
parse_episode('wilford')
# => nil
parse_episode('simpsons_S04E12_monorail')
# => ["simpsons", "S04", "E12", "monorail"]
parse_episode('simpsons.S04E12')
# => ["simpsons", "S04", "E12", ""]
For example I have url string like:
https://abc.s3-something.amazonaws.com/subfolder/1234/5.html?X-Amz-Credential=abcd12bhhh34-1%2Fs3%2Faws4_request&X-Amz-Date=2016&X-Amz-Expires=3&X-Amz-SignedHeaders=host&X-Amz-Signature=abcd34hhhhbfbbf888ksdskj
From this string I need to extract number 1234 which comes after subfolder/. I tried with gsub but no luck. Any help would be appreciated.
Suppose your url is saved in a variable called url.
Then the following should return 1234
url.match(/subfolder\/(\d*)/)[1]
Explanation:
url.match(/ # call the match function which takes a regex
subfolder\/ # search for the first appearance of the string 'subfolder/'
# note: we must escape the `/` so we don't end the regex early
(\d*) # match any number of digits in a capture group,
/)[1] # close the regex and return the first capture group
lwassink has the right idea, but it can be done more simply. If subfolder is always the same:
url = "https://abc.s3-something.amazonaws.com/subfolder/1234/5.html?X-Amz-Credential=abcd12bhhh34-1%2Fs3%2Faws4_request&X-Amz-Date=2016&X-Amz-Expires=3&X-Amz-SignedHeaders=host&X-Amz-Signature=abcd34hhhhbfbbf888ksdskj"
url[/subfolder\/\K\d+/]
# => "1234"
The \K discards the matched text up to that point, so only "1234" is returned.
If you want to get the number after any subfolder, and the domain name is always the same, you might do this instead:
url[%r{amazonaws\.com/[^/]+/\K\d+}]
# => "1234"
s.split('/')[4]
Add a .to_i at the end if you like.
Or, to key it on a substring like you asked for...
a = s.split '/'
a[a.find_index('subfolder') + 1]
Or, to do it as a one-liner I suppose you could:
s.split('/').tap { |a| #i = 1 + a.find_index('subfolder')}[#i]
Or, since I am a damaged individual, I would actually write that:
s.split('/').tap { |a| #i = 1 + (a.find_index 'subfolder')}[#i]
url = 'http://abc/xyz'
index= url.index('/abc/')
url[index+5..length_of_string_you_want_to_extract]
Hope, that helps!
I am trying to use gsub or sub on a regex passed through terminal to ARGV[].
Query in terminal: $ruby script.rb input.json "\[\{\"src\"\:\"
Input file first 2 lines:
[{
"src":"http://something.com",
"label":"FOO.jpg","name":"FOO",
"srcName":"FOO.jpg"
}]
[{
"src":"http://something123.com",
"label":"FOO123.jpg",
"name":"FOO123",
"srcName":"FOO123.jpg"
}]
script.rb:
dir = File.dirname(ARGV[0])
output = File.new(dir + "/output_" + Time.now.strftime("%H_%M_%S") + ".json", "w")
open(ARGV[0]).each do |x|
x = x.sub(ARGV[1]),'')
output.puts(x) if !x.nil?
end
output.close
This is very basic stuff really, but I am not quite sure on how to do this. I tried:
Regexp.escape with this pattern: [{"src":".
Escaping the characters and not escaping.
Wrapping the pattern between quotes and not wrapping.
Meditate on this:
I wrote a little script containing:
puts ARGV[0].class
puts ARGV[1].class
and saved it to disk, then ran it using:
ruby ~/Desktop/tests/test.rb foo /abc/
which returned:
String
String
The documentation says:
The pattern is typically a Regexp; if given as a String, any regular expression metacharacters it contains will be interpreted literally, e.g. '\d' will match a backlash followed by ‘d’, instead of a digit.
That means that the regular expression, though it appears to be a regex, it isn't, it's a string because ARGV only can return strings because the command-line can only contain strings.
When we pass a string into sub, Ruby recognizes it's not a regular expression, so it treats it as a literal string. Here's the difference in action:
'foo'.sub('/o/', '') # => "foo"
'foo'.sub(/o/, '') # => "fo"
The first can't find "/o/" in "foo" so nothing changes. It can find /o/ though and returns the result after replacing the two "o".
Another way of looking at it is:
'foo'.match('/o/') # => nil
'foo'.match(/o/) # => #<MatchData "o">
where match finds nothing for the string but can find a hit for /o/.
And all that leads to what's happening in your code. Because sub is being passed a string, it's trying to do a literal match for the regex, and won't be able to find it. You need to change the code to:
sub(Regexp.new(ARGV[1]), '')
but that's not all that has to change. Regexp.new(...) will convert what's passed in into a regular expression, but if you're passing in '/o/' the resulting regular expression will be:
Regexp.new('/o/') # => /\/o\//
which is probably not what you want:
'foo'.match(/\/o\//) # => nil
Instead you want:
Regexp.new('o') # => /o/
'foo'.match(/o/) # => #<MatchData "o">
So, besides changing your code, you'll need to make sure that what you pass in is a valid expression, minus any leading and trailing /.
Based on this answer in the thread Convert a string to regular expression ruby, you should use
x = x.sub(/#{ARGV[1]}/,'')
I tested it with this file (test.rb):
puts "You should not see any number [0123456789].".gsub(/#{ARGV[0]}/,'')
I called the file like so:
ruby test.rb "\d+"
# => You should not see any number [].
Is there a way to do this?
I have an array:
["file_1.jar", "file_2.jar","file_3.pom"]
And I want to keep only "file_3.pom", what I want to do is something like this:
array.drop_while{|f| /.pom/.match(f)}
But This way I keep everything in array but "file_3.pom" is there a way to do something like "not_match"?
I found these:
f !~ /.pom/ # => leaves all elements in array
OR
f !~ /*.pom/ # => leaves all elements in array
But none of those returns what I expect.
How about select?
selected = array.select { |f| /.pom/.match(f) }
p selected
# => ["file_3.pom"]
Hope that helps!
In your case you can use the Enumerable#grep method to get an array of the elements that matches a pattern:
["file_1.jar", "file_2.jar", "file_3.pom"].grep(/\.pom\z/)
# => ["file_3.pom"]
As you can see I've also slightly modified your regular expression to actually match only strings that ends with .pom:
\. matches a literal dot, without the \ it matches any character
\z anchor the pattern to the end of the string, without it the pattern would match .pom everywhere in the string.
Since you are searching for a literal string you can also avoid regular expression altogether, for example using the methods String#end_with? and Array#select:
["file_1.jar", "file_2.jar", "file_3.pom"].select { |s| s.end_with?('.pom') }
# => ["file_3.pom"]
If you whant to keep only Strings witch responds on regexp so you can use Ruby method keep_if.
But this methods "destroy" main Array.
a = ["file_1.jar", "file_2.jar","file_3.pom"]
a.keep_if{|file_name| /.pom/.match(file_name)}
p a
# => ["file_3.pom"]
I have a string which looks like:
hello/world/1.9.2-some-text
hello/world/2.0.2-some-text
hello/world/2.11.0
Through regex I want to get the string after last '/' and until end of line i.e. in above examples output should be 1.9.2-some-text, 2.0.2-some-text, 2.11.0
I tried this - ^(.+)\/(.+)$ which returns me an array of which first object is "hello/world" and 2nd object is "1.9.2-some-text"
Is there a way to just get "1.9.2-some-text" as the output?
Try using a negative character class ([^…]) like this:
[^\/]+$
This will match one or more of any character other than / followed by the end of the string.
You can use a negated match here.
'hello/world/1.9.2-some-text'.match(Regexp.new('[^/]+$'))
# => "1.9.2-some-text"
Meaning any character except: / (1 or more times) followed by the end of the string.
Although, the simplest way would be to split the string.
'hello/world/1.9.2-some-text'.split('/').last
# => "1.9.2-some-text"
OR
'hello/world/1.9.2-some-text'.split('/')[-1]
# => "1.9.2-some-text"
If you do not need to use a regex, the ordinary way of doing such thing is:
File.basename("hello/world/1.9.2-some-text")
#=> "1.9.2-some-text"
This is one way:
s = 'hello/world/1.9.2-some-text
hello/world/2.0.2-some-text
hello/world/2.11.0'
s.lines.map { |l| l[/.*\/(.*)/,1] }
#=> ["1.9.2-some-text", "2.0.2-some-text", "2.11.0"]
You said, "in above examples output should be 1.9.2-some-text, 2.0.2-some-text, 2.11.0". That's neither a string nor an array, so I assumed you wanted an array. If you want a string, tack .join(', ') onto the end.
Regex's are naturally "greedy", so .*\/ will match all characters up to and including the last / in each line. 1 returns the contents of the capture group (.*) (capture group 1).