I have the following line
'passenger (2.2.5, 2.0.6)'.match(//)[0]
which obviously doesn't match anything yet
I want to return the just the content of (2.2.5, so everything after the open parentheses and before the comma.
How would I do this?
Beanish solution fails on more than 2 version numbers, you should use something like:
>> 'passenger (2.2.5, 2.0.6, 1.8.6)'.match(/\((.*?),/)[1] # => "2.2.5"
'passenger (2.2.5, 2.0.6)'.match(/\((.*),/)[1]
if you use the $1 element it is the group that is found within the ( )
#!/usr/bin/env ruby
s = 'passenger (2.2.5, 2.0.6)'
p s.scan(/(?:\(|, *)([^,)]*)/).flatten # => ["2.2.5", "2.0.6"]
Related
How can I get the username without the # symbol?
That's everything between # and any non-word character.
message = <<-MESSAGE
From #victor with love,
To #andrea,
and CC goes to #ghost
MESSAGE
Using a Ruby regular expression, I tried
username_pattern = /#\w+/
I will like to get the following output
message.scan(username_pattern)
#=> ["victor", "andrea", "ghost"]
Use look behind
(?<=#)\w+
this will leave # symbol regex
I would go with:
message.scan(/(?<=#)\w+/)
#=> ["victor","andrea","ghost"]
You might want to read about look-behind regexp.
You could match the # and then capture one or more times a word character in a capturing group
#(\w+)
username_pattern = /#(\w+)/
Regex demo
Try this
irb(main):010:0> message.scan(/#(\w+)/m).flatten
=> ["victor", "andrea", "ghost"]
I am new to ruby and I want to do the following action to remove last "_val3" in ruby:
$ val="val1_val2_val3"
$ echo ${val%_*}
val1_val2
I used to use echo ${val%_*} to get "val1_val2", but i do not how do this in ruby.
Also, how to get "val1"?
Is there a good way to do them?
Not a ruby expert but I'll get the ball rolling with a regular expression:
a.sub /_[^_]*$/, ''
Match an underscore followed by any number of non-underscores at the end of the string. Replace with nothing.
You can use a single gsub to get your expected o/p,
a = "a-b_c_d"
# => "a-b_c_d"
a.gsub /_[a-z]*$/, ''
# => "a-b_c"
Or, you can use ruby split and join,
a.split("_")[0..-2].join("_")
# => "a-b_c"
String#rpartition would probably work:
'a-b_c_d'.rpartition('_') #=> ["a-b_c", "_", "d"]
rpartition looks for the last '_' and returns an array containing the part before it, the separator itself and the part after it.
How can I get the filename without the extensions? For example, input of "/dir1/dir2/test.html.erb" should return "test".
In actual code I will passing in __FILE__ instead of "/dir1/dir2/test.html.erb".
Read documentation:
basename(file_name [, suffix] ) → base_name
Returns the last component of the filename given in file_name, which
can be formed using both File::SEPARATOR and File::ALT_SEPARATOR as
the separator when File::ALT_SEPARATOR is not nil. If suffix is given
and present at the end of file_name, it is removed.
=> File.basename('public/500.html', '.html')
=> "500"
in you case:
=> File.basename("test.html.erb", ".html.erb")
=> "test"
How about this
File.basename(f, File.extname(f))
returns the file name without the extension.. works for filenames with multiple '.' in it.
In case you don't know the extension you can combine File.basename with File.extname:
filepath = "dir/dir/filename.extension"
File.basename(filepath, File.extname(filepath)) #=> "filename"
Pathname provides a convenient object-oriented interface for dealing with file names.
One method lets you replace the existing extension with a new one, and that method accepts the empty string as an argument:
>> Pathname('foo.bar').sub_ext ''
=> #<Pathname:foo>
>> Pathname('foo.bar.baz').sub_ext ''
=> #<Pathname:foo.bar>
>> Pathname('foo').sub_ext ''
=> #<Pathname:foo>
This is a convenient way to get the filename stripped of its extension, if there is one.
But if you want to get rid of all extensions, you can use a regex:
>> "foo.bar.baz".sub(/(?<=.)\..*/, '')
=> "foo"
Note that this only works on bare filenames, not paths like foo.bar/pepe.baz. For that, you might as well use a function:
def without_extensions(path)
p = Pathname(path)
p.parent / p.basename.sub(
/
(?<=.) # look-behind: ensure some character, e.g., for ‘.foo’
\. # literal ‘.’
.* # extensions
/x, '')
end
Split by dot and the first part is what you want.
filename = 'test.html.erb'
result = filename.split('.')[0]
Considering the premise, the most appropriate answer for this case (and similar cases with other extensions) would be something such as this:
__FILE__.split('.')[0...-1].join('.')
Which will only remove the extension (not the other parts of the name: myfile.html.erb here becomes myfile.html, rather than just myfile.
Thanks to #xdazz and #Monk_Code for their ideas. In case others are looking, the final code I'm using is:
File.basename(__FILE__, ".*").split('.')[0]
This generically allows you to remove the full path in the front and the extensions in the back of the file, giving only the name of the file without any dots or slashes.
name = "filename.100.jpg"
puts "#{name.split('.')[-1]}"
Yet understanding it's not a multiplatform solution, it'd work for unixes:
def without_extensions(path)
lastSlash = path.rindex('/')
if lastSlash.nil?
theFile = path
else
theFile = path[lastSlash+1..-1]
end
# not an easy thing to define
# what an extension is
theFile[0...theFile.index('.')]
end
puts without_extensions("test.html.erb")
puts without_extensions("/test.html.erb")
puts without_extensions("a.b/test.html.erb")
puts without_extensions("/a.b/test.html.erb")
puts without_extensions("c.d/a.b/test.html.erb")
I need to extract the last occurrence of a substring enclosed in _()_, e.g.
'a_long_(abc)_000' => abc
'a_long(string)_(def)_000' => def
'a_long_(string)_(abc)_blabla' => abc
Match using /_\((.*?)\)_/ and grab the last match:
>> 'a_long_(string)_foo_(abc)_blabla'.scan(/_\((.*?)\)_/)[-1]
=> ["abc"]
Smth like this:
str[/.*_\((.*?)\)_/,1]
You can also use the regex:
.*_\((.*?)\)_
See it
This this:
\(([^\)]+)\)_[a-zA-Z0-9]*$
$1 should be your string
I have the following regular expression in Ruby:
\<name\>(.+)\<\/name\>
Within in if statement, like so:
if line =~ /\<name\>(.+)\<\/name\>/
Is there any way to get the value of the group (.+)?
Thanks in advance!
It is in the variable $1
Rather than use regex to parse XML or HTML, use a real parser. I like Nokogiri:
require 'nokogiri'
doc = Nokogiri::XML('<somecontainingtags><name>blah</name></somecontainingtags>')
# find all occurences
doc.search('//name').map {|n| n.inner_text } # => ["blah"]
# find the first occurance
doc.at('//name').inner_text # => "blah"