Replacing a %20 with a space in Ruby - ruby

I've currently got a string that reads something like ["green%20books"] and I'd like it to read ["green books"].
I thought Googling for this would yield a result pretty quickly but everyone just wants to turn spaces into %20s. Not the other way around.
Any help would be much appreciated!
Edit:
This is the function I'm working with and I'm confused where in here to decode the URL. I tried removing the URI.encode text but that broke the function.
def self.get_search_terms(search_url)
hash = CGI.parse(URI.parse(URI.encode(search_url)).query) #returns a hash
keywords = []
hash.each do |key, value|
if key == "q" || key == "p"
keywords << value
end
end
keywords
end

you can use the 'unencode' method of URI. (aliased as decode)
require 'uri'
URI.decode("green%20books")
# => "green books"
this will not only replaces "%20" with space, but every uri-encoded charcter, which I assume is what you want.
documentation

CGI::unescape will do what you want:
1.9.2-p320 :001 > require 'cgi'
=> true
1.9.2-p320 :002 > s = "green%20books"
=> "green%20books"
1.9.2-p320 :003 > CGI.unescape(s)
=> "green books"
Another option (as YenTheFirst mentioned) might be URI.decode. However, I read a discussion that it would be deprecated -- although that was in 2010.
Anyway, since you're asking about arrays, you would perhaps map using that method:
ary.map { |s| CGI.unescape(s) }

You can use regular expressions:
string = "green%20books"
string.gsub!('%20', ' ')
puts string

Related

Extract Date from string ruby

I have this string :
Rep. Barletta, Lou [R-PA-11] (Introduced 06/04/2015)
And I want to extract the date which is "06/04/2015". How do i do this in ruby?
I have tried to do something like this:
str[-1..-11]
but didnt work. Any suggestion? Thanks!
str = "Rep. Barletta, Lou [R-PA-11] (Introduced 06/04/2015)"
str.match(/(\d{2}\/\d{2}\/\d{4})/)[0]
#=> "06/04/2015"
This code matches anything that's in the format of 2 numbers/2 numbers/4 numbers and returns it.
If there's a possibility of having XX/XX/XXXX somewhere else in the string, I'd probably use the following code instead:
str = "Rep. Barletta, Lou [R-PA-11] (Introduced 06/04/2015)"
str.match(\(Introduced (\d{2}\/\d{2}\/\d{4})\)$)[0]
#=> "06/04/2015"
This searches for (Introduced XX/XX/XXXX) and grabs the date from that in particular.
Date has a parse method, which happens to just work.
require 'date'
str = "Rep. Barletta, Lou [R-PA-11] (Introduced 06/04/2015)"
p d = Date.parse(str) # => #<Date: 2015-04-06 ((2457119j,0s,0n),+0s,2299161j)>
str[-11..-2] if the position of the date does not change
I agree with Piccolo's comment. Here is a simple regular expression you can try in irb. I recommend experimenting in irb to learn some rudimentary Ruby regular expressions.
For example, /.+([0-9]{2}\/[0-9]{2}\/[0-9]{4}).+/ looks for anything followed by two digits, slash, two digits, slash, four digits, then anything:
$ irb
2.2.0 :001 > s='Rep. Barletta, Lou [R-PA-11] (Introduced 06/04/2015)'
2.2.0 :009 > /.+([0-9]{2}\/[0-9]{2}\/[0-9]{4}).+/ =~ s && $1
=> "06/04/2015"
2.2.0 :010 >
#steenslag's answer looks for valid dates (unlike the other answers), but could still be tripped up:
str = "The first 10 may go 15/15/2015 with Lou (Introduced 06/04/2015)"
Date.parse(str)
#=> #<Date: 2015-05-10 ((2457153j,0s,0n),+0s,2299161j)>
To ensure the date is in the specified format, you could do the following:
require 'date'
def extract_date(str, fmt)
a = str.each_char
.each_cons(10)
.find { |a| Date.strptime(a.join, fmt) rescue nil }
a ? a.join : nil
end
For str as above:
extract_date(str, '%d/%m/%Y')
#=> "06/04/2015"
A second example:
extract_date("15/15/2015", '%d/%m/%Y')
#=> nil

URL Encoding in ruby

I have a block of code:
temp = "Cancel"
puts CGI::escape(words[1])
puts "\n"
puts CGI::escape(temp)
puts "\n"
puts words[1]
puts "\n"
puts temp
puts "\n"
My output is:
%00C%00a%00n%00c%00e%00l%00
Cancel
Cancel
Cancel
I think it's fair to assume that the issue here is the way I set up my words array. However, I was wondering if this is common behavior which has a solution? If not, what could I be doing wrong that would cause this?
My words array is set up by reading data from a file, then splitting each line and extracting the information I need, so it's nothing too complex.
You have NUL bytes in your string. puts just ignores them.
1.9.2p290 :016 > puts "Fo\0oooo"
Fooooo
=> nil
with inspect you can see them:
1.9.2p290 :017 > puts "Fo\0oooo".inspect
"Fo\u0000oooo"
=> nil
and here the output of CGI::escape
1.9.2p290 :018 > puts CGI::escape("Fooo\0ooo")
Fooo%00ooo
=> nil
edit:
The quick and dirty solution would be to just remove them:
"Fooooo\0ooo".gsub(/\0/, "")
=> "Foooooooo"
but as you have NUL bytes in front of every char, you should better check your code for reading the file. If you'd provide the code, it would be easier to come up with a solution.

Ruby: How to get the first character of a string

How can I get the first character in a string using Ruby?
Ultimately what I'm doing is taking someone's last name and just creating an initial out of it.
So if the string was "Smith" I just want "S".
You can use Ruby's open classes to make your code much more readable. For instance, this:
class String
def initial
self[0,1]
end
end
will allow you to use the initial method on any string. So if you have the following variables:
last_name = "Smith"
first_name = "John"
Then you can get the initials very cleanly and readably:
puts first_name.initial # prints J
puts last_name.initial # prints S
The other method mentioned here doesn't work on Ruby 1.8 (not that you should be using 1.8 anymore anyway!--but when this answer was posted it was still quite common):
puts 'Smith'[0] # prints 83
Of course, if you're not doing it on a regular basis, then defining the method might be overkill, and you could just do it directly:
puts last_name[0,1]
If you use a recent version of Ruby (1.9.0 or later), the following should work:
'Smith'[0] # => 'S'
If you use either 1.9.0+ or 1.8.7, the following should work:
'Smith'.chars.first # => 'S'
If you use a version older than 1.8.7, this should work:
'Smith'.split(//).first # => 'S'
Note that 'Smith'[0,1] does not work on 1.8, it will not give you the first character, it will only give you the first byte.
"Smith"[0..0]
works in both ruby 1.8 and ruby 1.9.
For completeness sake, since Ruby 1.9 String#chr returns the first character of a string. Its still available in 2.0 and 2.1.
"Smith".chr #=> "S"
http://ruby-doc.org/core-1.9.3/String.html#method-i-chr
In MRI 1.8.7 or greater:
'foobarbaz'.each_char.first
Try this:
>> a = "Smith"
>> a[0]
=> "S"
OR
>> "Smith".chr
#=> "S"
In Rails
name = 'Smith'
name.first
>> s = 'Smith'
=> "Smith"
>> s[0]
=> "S"
Another option that hasn't been mentioned yet:
> "Smith".slice(0)
#=> "S"
Because of an annoying design choice in Ruby before 1.9 — some_string[0] returns the character code of the first character — the most portable way to write this is some_string[0,1], which tells it to get a substring at index 0 that's 1 character long.
Try this:
def word(string, num)
string = 'Smith'
string[0..(num-1)]
end
If you're using Rails You can also use truncate
> 'Smith'.truncate(1, omission: '')
#=> "S"
or for additional formatting:
> 'Smith'.truncate(4)
#=> "S..."
> 'Smith'.truncate(2, omission: '.')
#=> "S."
While this is definitely overkill for the original question, for a pure ruby solution, here is how truncate is implemented in rails
# File activesupport/lib/active_support/core_ext/string/filters.rb, line 66
def truncate(truncate_at, options = {})
return dup unless length > truncate_at
omission = options[:omission] || "..."
length_with_room_for_omission = truncate_at - omission.length
stop = if options[:separator]
rindex(options[:separator], length_with_room_for_omission) || length_with_room_for_omission
else
length_with_room_for_omission
end
"#{self[0, stop]}#{omission}"
end
Other way around would be using the chars for a string:
def abbrev_name
first_name.chars.first.capitalize + '.' + ' ' + last_name
end
Any of these methods will work:
name = 'Smith'
puts name.[0..0] # => S
puts name.[0] # => S
puts name.[0,1] # => S
puts name.[0].chr # => S

Converting upper-case string into title-case using Ruby

I'm trying to convert an all-uppercase string in Ruby into a lower case one, but with each word's first character being upper case. Example:
convert "MY STRING HERE" to "My String Here".
I know I can use the .downcase method, but that would make everything lower case ("my string here"). I'm scanning all lines in a file and doing this change, so is there a regular expression I can use through ruby to achieve this?
Thanks!
If you're using Rails (really all you need is ActiveSupport, which is part of Rails), you can use titleize:
"MY STRING HERE".titleize
# => "My String Here"
If you're using plain Ruby but don't mind loading a small amount of ActiveSupport you can require it first:
require 'active_support/core_ext/string/inflections'
# => true
"MY STRING HERE".titleize
# => "My String Here"
N.B. By default titleize doesn't handle acronyms well and will split camelCaseStrings into separate words. This may or may not be desirable:
"Always use SSL on your iPhone".titleize
# => "Always Use Ssl On Your I Phone"
You can (partially) address this by adding "acronyms":
require 'active_support/core_ext/string/inflections' # If not using Rails
ActiveSupport::Inflector.inflections do |inflect|
inflect.acronym 'SSL'
inflect.acronym 'iPhone'
end
"Always use SSL on your iPhone".titleize
# => "Always Use SSL On Your IPhone"
For those who speak the Queen's English (or who struggle to spell titleize), there's no .titleise alias but you can use .titlecase instead.
"HELLO WORLD HOW ARE YOU".gsub(/\w+/) do |word|
word.capitalize
end
#=> "Hello World How Are You"
While trying to come up with my own method (included below for reference), I realized that there's some pretty nasty corner cases. Better just use the method already provided in Facets, the mostest awesomest Ruby library evar:
require 'facets/string/titlecase'
class String
def titleize
split(/(\W)/).map(&:capitalize).join
end
end
require 'test/unit'
class TestStringTitlecaseAndTitleize < Test::Unit::TestCase
def setup
#str = "i just saw \"twilight: new moon\", and man! it's crap."
#res = "I Just Saw \"Twilight: New Moon\", And Man! It's Crap."
end
def test_that_facets_string_titlecase_works
assert_equal #res, #str.titlecase
end
def test_that_my_own_broken_string_titleize_works
assert_equal #res, #str.titleize # FAIL
end
end
If you want something that more closely complies to typical writing style guidelines (i.e. does not capitalize words like "and"), there are a couple of "titleize" gems on GitHub.
From ActiveSupport
"MY STRING HERE".gsub(/\b('?[a-z])/) { $1.capitalize }
If you are using Rails/ActiveSupport, the method is already available for free.
string = "MY STRING HERE"
string.split(" ").map {|word| word.capitalize}.join(" ")
The way this works:
The .split(" ") splits it on spaces, so now we have an array that looks like ["my", "string", "here"]. The map call iterates over each element of the array, assigning it to temporary variable word, which we then call capitalize on. Now we have an array that looks like ["My", "String", "Here"], and finally we turn that array back into a string by joining each element with a space (" ").
"MY STRING HERE".titlecase
Does the job (it's a method in the Rails gem, however)
http://apidock.com/rails/String/titlecase
Unicode-aware titlecase for Ruby 2.4.0+:
class String
def titlecase
split(/([[:alpha:]]+)/).map(&:capitalize).join
end
end
>> "я только что посмотрел \"леди исчезает\", и это чума!".titlecase
=> "Я Только Что Посмотрел \"Леди Исчезает\", И Это Чума!"
(based on https://stackoverflow.com/a/1792102/788700)
To catch any edge case such as:
str = "rUby on rAils"
Don't use:
str.titleize
Output: R Uby On R Ails
Use instead:
str.downcase.titleize
Output: Ruby On Rails
I've try to improve code... ready for critics and suggestions.
class Book
attr_accessor :title
def title=(new_title)
notcap=%w(and the a in of an)
str=''
new_title.gsub(/(\w|\s)\w+/) do |word|
word.strip!
if not notcap.include? word
word.capitalize!
end
str += ' ' + word
end
str.strip!
str = str[0].upcase + str[1..-1]
#title = str
end
end
The ruby core itself has no support to convert a string from upper (word) case to capitalized word case.
So you need either to make your own implementation or use an existing gem.
There is a small ruby gem called lucky_case which allows you to convert a string from any of the 10+ supported cases to another case easily:
require 'lucky_case'
# to get capital word case as string
LuckyCase.capital_word_case('MY STRING HERE') # => 'My String Here'
# or the opposite way
LuckyCase.upper_word_case('Capital Word Case') # => 'MY STRING HERE'
You can even monkey patch the String class if you want to:
require 'lucky_case/string'
'MY STRING HERE'.capital_word_case # => 'My String Here'
'MY STRING HERE'.capital_word_case! # => 'My String Here' and overwriting original
Have a look at the offical repository for more examples and documentation:
https://github.com/magynhard/lucky_case
Capitalizes every word in a sentence using ruby, without regex.. because unfortunately those scare me
class Book
attr_accessor :title
def title=(new_title)
result = []
words = new_title.split(' ')
words.each do |word|
capitalized = word[0].upcase + word[1..word.length].downcase
result.push(capitalized)
end
#title = result.join(' ')
end
end

Remove a character at an index position in Ruby

Basically what the question says. How can I delete a character at a given index position in a string? The String class doesn't seem to have any methods to do this.
If I have a string "HELLO" I want the output to be this
["ELLO", "HLLO", "HELO", "HELO", "HELL"]
I do that using
d = Array.new(c.length){|i| c.slice(0, i)+c.slice(i+1, c.length)}
I dont know if using slice! will work here, because it will modify the original string, right?
Won't Str.slice! do it? From ruby-doc.org:
str.slice!(fixnum) => fixnum or nil [...]
Deletes the specified portion from str, and returns the portion deleted.
If you're using Ruby 1.8, you can use delete_at (mixed in from Enumerable), otherwise in 1.9 you can use slice!.
Example:
mystring = "hello"
mystring.slice!(1) # mystring is now "hllo"
# now do something with mystring
$ cat m.rb
class String
def maulin! n
slice! n
self
end
def maulin n
dup.maulin! n
end
end
$ irb
>> require 'm'
=> true
>> s = 'hello'
=> "hello"
>> s.maulin(2)
=> "helo"
>> s
=> "hello"
>> s.maulin!(1)
=> "hllo"
>> s
=> "hllo"
To avoid needing to monkey patch String you can make use of tap:
"abc".tap {|s| s.slice!(2) }
=> "ab"
If you need to leave your original string unaltered, make use of dup, eg. abc.dup.tap.
I did something like this
c.slice(0, i)+c.slice(i+1, c.length)
Where c is the string and i is the index position I want to delete. Is there a better way?

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