How could I split commas excepts it's in double quotes - ruby

s1 ='a,b,c,"x,y,z" '
m1 = s1.split(',')
"x,y,z" should not be splitted by comma
The expected result should be ['a','b','c',"x,y,z"], total size is 4
How could I do that in Ruby

Use the csv module:
irb(main):001:0> require 'csv'
=> true
irb(main):002:0> CSV.parse_line('a,b,c,"x,y,z"')
=> ["a", "b", "c", "x,y,z"]

Try this:
s1 ='a,b,c,"x,y,z" '
quotes = s1.match(/".+"/)
s1.split(/,(?![#{quotes}])|,(?=")/)

Could it be? Is it possible? Do I finally have a chance to use Ruby's bordering-on-bizarre flip-flop operator?
Let's try:
str ='a,b,c,"x,y,z",d,e,"1,2,3",f '
u = ''
str.split(?,).each_with_object([]) do |s,a|
t = s.strip
if (t[0]==?") .. (t[-1]==?")
u = '' if t[0]==?"
u << t
if t[-1]==?"
a << u
else
u << ?,
end
else
a << t
end
end
#=> ["a", "b", "c", "\"x,y,z\"", "d", "e", "\"1,2,3\"", "f"]

You can do a one liner def like this that will separate the string by commas, unless the commas are inside simple OR double quotes
def separate params
params.split(/(?!\B\b('|")[^\"']*),(?![^\"']*('|")\B\b)/)
end

Related

how I could do a gsub with array elements?

How I could replaces a string like this
I think something like this
inputx.gsub(/variable1/,string1.split(";")[i])
But I dont know How I could do this code
name1;variable1
name;variable1
name3;variable1
by
dog;watch;rock
For obtain this
name1;dog
name;watch
name3;rock
string1 => dog;watch;rock ; this string Im trying to split for replace each string variable1
Please help me
subst = "dog;watch;rock".split ';'
input.gsub(/variable1/) do subst.shift end
#⇒ "name1;dog \n name;watch \n name3;rock"
Given (assuming) this input:
inputx = <<-EOD
name1;variable1
name;variable1
name3;variable1
EOD
#=> "name1;variable1\nname;variable1\nname3;variable1\n"
string1 = 'dog;watch;rock'
#=> "dog;watch;rock"
You can chain gsub and with_index to perform a replacement based on its index:
inputx.gsub('variable1').with_index { |_, i| string1.split(';')[i] }
#=> "name1;dog\nname;watch\nname3;rock\n"
You could also perform the split beforehand:
values = string1.split(';')
#=> ["dog", "watch", "rock"]
inputx.gsub('variable1').with_index { |_, i| values[i] }
#=> "name1;dog\nname;watch\nname3;rock\n"
I'm not sure there's a way to do it using .gsub(). One simple way to achieve what you want to is the following:
str = "dog;watch;rock"
array = str.split(";")
array.each_with_index do |str, i|
array[i] = "name#{i + 1};#{str}"
end
puts array
Output:
name1;dog
name2;watch
name3;rock
file intro2 => dog;watch;rock
file intro
name1;variable1
name;variable1
name3;variable1
ruby code
ruby -e ' n=0; input3= File.read("intro");string1= File.read("intro2") ;input3x=input3.gsub("variable1") { val =string1.split(";")[n].to_s; n+=1; val } ;print input3x' >gggf

Keep characters and whitespace in ruby method

Building out a Rot method to solve encryption. I have something that is working but takes out whitespaces and any characters that are included. Was going to use bytes instead of chars then turn it back into a string once I have the byte code but I can't seem to get it working. How would you go about keeping those in place from this code:
code
def rot(x, string, encrypt=true)
alphabet = Array("A".."Z") + Array("a".."z")
results = []
if encrypt == true
key = Hash[alphabet.zip(alphabet.rotate(x))]
string.chars.each do |i|
if ('a'..'z').include? i
results << key.fetch(i).downcase
elsif ('A'..'Z').include? i
results << key.fetch(i).upcase
end
end
return results.join
else
key_false = Hash[alphabet.zip(alphabet.rotate(26 - x))]
string.chars.each do |i|
if ('a'..'z').include? i
results << key_false.fetch(i).downcase
elsif ('A'..'Z').include? i
results << key_false.fetch(i).upcase
end
end
return results.join
end
end
puts rot(10, "Hello, World")
=> RovvyGybvn
puts rot(10, "Rovvy, Gybvn", false)
=> HelloWorld
Thanks for your help in advance!
Just add to both if blocks an else condition like this:
if ('a'..'z').include? i
# ...
elsif ('A'..'Z').include? i
# ...
else
results << i
end
Which will add all non A-z characters untouched to the output.
I've noticed some issues with your code:
Broken replacement hash
This is the biggest problem - your replacement hash is broken. I'm using a smaller alphabet for demonstration purposes, but this applies to 26 characters as well:
uppercase = Array("A".."C")
lowercase = Array("a".."c")
alphabet = uppercase + lowercase
#=> ["A", "B", "C", "a", "b", "c"]
You build the replacement hash via:
x = 1
key = Hash[alphabet.zip(alphabet.rotate(x))]
#=> {"A"=>"B", "B"=>"C", "C"=>"a", "a"=>"b", "b"=>"c", "c"=>"A"}
"C"=>"a" and "c"=>"A" are referring to the wrong character case. This happens because you rotate the entire alphabet at once:
alphabet #=> ["A", "B", "C", "a", "b", "c"]
alphabet.rotate(x) #=> ["B", "C", "a", "b", "c", "A"]
Instead. you have to rotate the uppercase and lowercase letter separately:
uppercase #=> ["A", "B", "C"]
uppercase.rotate(x) #=> ["B", "C", "A"]
lowercase #=> ["a", "b", "c"]
lowercase.rotate(x) #=> ["B", "C", "A"]
and concatenate the rotated parts afterwards. Either:
key = Hash[uppercase.zip(uppercase.rotate(x)) + lowercase.zip(lowercase.rotate(x))]
#=> {"A"=>"B", "B"=>"C", "C"=>"A", "a"=>"b", "b"=>"c", "c"=>"a"}
or:
key = Hash[(uppercase + lowercase).zip(uppercase.rotate(x) + lowercase.rotate(x))]
#=> {"A"=>"B", "B"=>"C", "C"=>"A", "a"=>"b", "b"=>"c", "c"=>"a"}
Replacing the characters
Back to a full alphabet:
uppercase = Array("A".."Z")
lowercase = Array("a".."z")
x = 10
key = Hash[uppercase.zip(uppercase.rotate(x)) + lowercase.zip(lowercase.rotate(x))]
Having a working replacement hash makes replacing the characters almost trivial:
string = "Hello, World!"
result = ""
string.each_char { |char| result << key.fetch(char, char) }
result
#=> "Rovvy, Gybvn!"
I've changed result from an array to a string. It also has a << method and you don't have to join it afterwards.
Hash#fetch works almost like Hash#[], but you can pass a default value that is returned if the key is not found in the hash:
key.fetch("H", "H") #=> "R" (replacement value)
key.fetch("!", "!") #=> "!" (default value)
Handling encryption / decryption
You're duplicating a lot of code to handle the decryption part. But there's a much easier way - just reverse the direction:
rot(10, "Hello") #=> "Rovvy"
rot(10, "Rovvy", false) #=> "Hello"
rot(-10, "Rovvy") #=> "Hello"
So within your code, you can write:
x = -x unless encrypt
Putting it all together
def rot(x, string, encrypt = true)
uppercase = Array("A".."Z")
lowercase = Array("a".."z")
x = -x unless encrypt
key = Hash[uppercase.zip(uppercase.rotate(x)) + lowercase.zip(lowercase.rotate(x))]
result = ""
string.each_char { |char| result << key.fetch(char, char) }
result
end
rot(10, "Hello, World!") #=> "Rovvy, Gybvn!"
rot(10, "Rovvy, Gybvn!", false) #=> "Hello, World!"

Use single quote in string inspection

I have the following program:
args = ["a", "b"]
cmd_args = args.map{|x| x.inspect}
str = cmd_args.join(' ')
puts str
The output is:
"a" "b"
I expect the output to be like the following (sub-string quoted with ' instead of "):
'a' 'b'
I don't want to do a gsub after string inspect because, in my real system, substring might contain ". For example:
args = ['a"c', "b"]
cmd_args = args.map{|x| x.inspect.gsub('"', '\'')}
str = cmd_args.join(' ')
puts str
will output:
'a\'c' 'b'
The " between a and c is wrongly replaced. My expected output is:
'a"c' 'b'
How can I make string inspect to quote strings with ' instead of "?
s = 'a"c'.inspect
s[0] = s[-1] = "'"
puts s.gsub("\\\"", "\"") #=> 'a"c'
You can't force String#inspect to use a single quote without rewriting or overwriting it.
Instead of x.inspect, you could substitute "'#{x}'", but then you would have to make sure you escape any ' characters that appear in x.
Here it is, working:
args = ["a", "b"]
cmd_args = args.map{|x| "'#{x}'" }
str = cmd_args.join(' ')
puts str
The output is:
'a' 'b'

Find all the possible permutations using Ruby and recursion

I've been trying to solve a simple quiz question to find all the possible permutation of a string using Ruby and recursion.
I have the following Ruby code:
def permutation(string)
return [string] if string.size < 2
chr = string.chars.first
perms = permutation(string[1..-1])
result = []
for perm in perms
for i in (0..perm.size)
result << (perm[0..i] + chr + perm[i..-1])
end
end
return result
end
Whenever I try to test the code with puts permutation("abc") I get the following output:
cacbc
cbabc
cbcac
cbca
cacb
cbab
cba
Theoretically speaking it's supposed to be a very simple and straightforward problem, but I'm sure I'm doing something wrong. Most probably it's something with the ranges of the loops. And I know that Ruby Array class has instance method permutation to do that but I'm trying to solve it for practising.
Please note that the complexity is O(N!) for the current implementation. Is there anyway to enhance the performance further?
To see what the difficulty may be, let's try it with an even simpler example:
string = "ab"
Your desired result is ["ab", "ba"]. Let's see what you get:
string.size #=> 2
so we don't return when
return [string] if string.size < 2
#=> return ["ab"] if "ab".size < 2
is executed.
Next we calculate:
chr = string.chars.first #=> "a"
Notice that a more direct way of making this calculation is as follows:
chr = string[0] #=> "a"
or, better, using String#chr,
chr = string.chr #=> "a"
The latter illustrates why chr is not the best choice for the variable name.
Next
perms = permutation(string[1..-1])
#=> = permutation("b")
I will now indent the return values to emphasize that we are calling permutation a second time. permuation's argument is:
string #=> "b"
Now when we execute:
return [string] if string.size < 2
#=> return ["b"] if "b".size < 2
we return ["b"], so (back to original call to permutation):
perms = ["b"]
to go with chr => "a", calculated earlier. Next:
result = []
for perm in perms
for i in (0..perm.size)
result << (perm[0..i] + chr + perm[i..-1])
end
end
As perms contains only the single element "b", the two for loops simplify to:
for i in (0.."b".size)
result << ("b"[0..i] + "a" + "b"[i..-1])
end
which is:
for i in (0..1)
result << ("b"[0..i] + "a" + "b"[i..-1])
end
Notice that "b"[0..0], "b"[0..1] and "b"[0..-1] all equal "b"[0], which is just "b", and "b"[1..-1] #=> ''. Therefore, when i => 0, we execute:
result << ("b"[0..0] + "a" + "b"[0..-1])
#=> result << ("b" + "a" + "b")
#=> result << "bab"
and when i => 1:
result << ("b"[0..1] + "a" + "b"[1..-1])
#=> result << ("b" + "a" + "")
#=> result << "ba"
so:
result => ["bab" + "ba"]
which clearly is not what you want.
What you need to do is is change the double for loops to:
for perm in perms
result << chr + perm
for i in (1..perm.size-1)
result << (perm[0..i-1] + chr + perm[i..-1])
end
result << perm + chr
end
which could be written more compactly by employing the method String#insert:
for perm in perms
for i in (0..perm.size)
result << perm.dup.insert(i,chr)
end
end
which you would normally see written like this:
perms.each_with_object([]) do |perm, result|
(0..perm.size).each { |i| result << perm.dup.insert(i,chr) }
end
Notice that we have to .dup the string before sending insert, as insert modifies the string.
Doing it like this, you don't need result = []. Neither do you need return result, as parms.each_with_object returns result and if there is no return statement, the method returns the last quantity calculated. Also, you don't need the temporary variable perms (or ch, if desired).
Putting this altogether, we have:
def permutation(string)
return [string] if string.size < 2
ch = string[0]
permutation(string[1..-1]).each_with_object([]) do |perm, result|
(0..perm.size).each { |i| result << perm.dup.insert(i,ch) }
end
end
Let's try it:
permutation("ab")
#=> ["ab", "ba"]
permutation("abc")
#=> ["abc", "bac", "bca", "acb", "cab", "cba"]
permutation("abcd")
#=> ["abcd", "bacd", "bcad", "bcda", "acbd", "cabd",
# "cbad", "cbda", "acdb", "cadb", "cdab", "cdba",
# "abdc", "badc", "bdac", "bdca", "adbc", "dabc",
# "dbac", "dbca", "adcb", "dacb", "dcab", "dcba"]
Eki, which one are you in the picture?
You can use Array#permutation:
def permutation(string)
string.permutation(string.size).to_a
end
permutation('abc'.chars)
# => [["a", "b", "c"], ["a", "c", "b"], ["b", "a", "c"], ["b", "c", "a"],
# ["c", "a", "b"], ["c", "b", "a"]]
UPDATE Without usign Array#permutation:
def permutation(string)
return [''] if string.empty?
chrs = string.chars
(0...string.size).flat_map { |i|
chr, rest = string[i], string[0...i] + string[i+1..-1]
permutation(rest).map { |sub|
chr + sub
}
}
end
permutation('abc')
# => ["abc", "acb", "bac", "bca", "cab", "cba"]

Why is my all? function not working? What's wrong with my syntax?

I originally wrote a method to take a word and find out if its vowels were in alphabetical order. I did it by using the code below:
def ordered_vowel_word?(word)
vowels = ["a", "e", "i", "o", "u"]
letters_arr = word.split("")
vowels_arr = letters_arr.select { |l| vowels.include?(l) }
(0...(vowels_arr.length - 1)).all? do |i|
vowels_arr[i] <= vowels_arr[i + 1]
end
end
However, I decided to try to change it by using an all? method. I tried to do so with the following code:
def ordered_vowel_word?(word)
vowels = ["a","e", "i", "o", "u"]
splitted_word = word.split("")
vowels_in_word = []
vowels_in_word = splitted_word.select {|word| vowels.include?(word)}
vowels_in_word.all? {|x| vowels_in_word[x]<= vowels_in_word[x+1]}
end
ordered_vowel_word?("word")
Anyone have any ideas why it isnt working? I would have expected this to work.
Also, if anyone has a better solution please feel free to post. Thanks!
Examples are:
it "does not return a word that is not in order" do
ordered_vowel_words("complicated").should == ""
end
it "handle double vowels" do
ordered_vowel_words("afoot").should == "afoot"
end
it "handles a word with a single vowel" do
ordered_vowel_words("ham").should == "ham"
end
it "handles a word with a single letter" do
ordered_vowel_words("o").should == "o"
end
it "ignores the letter y" do
ordered_vowel_words("tamely").should == "tamely"
end
Here is how I would do it:
#!/usr/bin/ruby
def ordered?(word)
vowels = %w(a e i o u)
check = word.each_char.select { |x| vowels.include?(x) }
# Another option thanks to #Michael Papile
# check = word.scan(/[aeiou]/)
puts check.sort == check
end
ordered?("afoot")
ordered?("outaorder")
Output is:
true
false
In your original example, you use the array values (String) as array indices which should be Integers when the all? method fires.
def ordered_vowel_word?(word)
vowels = ["a","e", "i", "o", "u"]
splitted_word = word.split("")
vowels_in_word = []
vowels_in_word = splitted_word.select {|word| vowels.include?(word)}
p vowels_in_word #=> ["o"]
vowels_in_word.all? {|x| vowels_in_word[x]<= vowels_in_word[x+1]}
end
p ordered_vowel_word?("word")
#=> `[]': no implicit conversion of String into Integer (TypeError)
vowels_in_word contains only 'o', and inside the vowels_in_word.all? {|x| vowels_in_word[x]<= vowels_in_word[x+1]} the expression vowels_in_word[x] means vowels_in_word["o"], which in-turn throws error as index can never be string.

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