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I have an array like this:
["1", "3", "2"]["2", "3", "1"]["3", "1", "2"]...
And want to transform it to an array that looks like this:
[132][231]..
What can i do? Thanks!
Using Enumerable#map, Array#join, and String#to_i:
a = ["1", "3", "2"],["2", "3", "1"],["3", "1", "2"]
a.map { |x| x.join.to_i } # => [132, 231, 312]
a.map { |x| [x.join.to_i] } # => [[132], [231], [312]]
a = [["1", "3", "2"],["2", "3", "1"],["3", "1", "2"]]
a.map{|e| [e.join.to_i]}
# => [[132], [231], [312]]
Ensure yourself that your variable has correct format and then as said
a = [["1", "3", "2"],["2", "3", "1"],["3", "1", "2"]]
a.map do |x|
x.join.to_i
end
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a = '123712638126378123681273'
i have
=> a = ['12','37', ...... ]
I tried to use split but I do not know how to order it
help me
I would do:
a.scan(/\d{2}/)
#=> ["12", "37", "12", "63", "81", "26", "37", "81", "23", "68", "12", "73"]
Input
a = '123712638126378123681273'
Code
p a.gsub(/.{2}/).to_a
Or
p a.chars.each_slice(2).map(&:join)
Output
["12", "37", "12", "63", "81", "26", "37", "81", "23", "68", "12", "73"]
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x = ["1", "2", "3", "4"]
#=> ["1", "2", "3", "4"]
x.split(", ")
#=> NoMethodError: undefined method `split' for ["1", "2", "3", "4"]:Array
The String#split method in ruby is used to divide a string into substrings
'a,b,c,d'.split(',') # => ["a", "b", "c", "d"]
You are trying to invoke Array#split (aka on an array object). As such array method doesn't exists, you get:
error undefined method split for ["1", "2", "3", "4"]:Array`
Arrays can't be split. You are probably thinking of splitting a string?
You will reach the desired value by simply x[0] for the 0 index, first object in the array.
This to any help?
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I currently want to get the numbers from 1 to 23 as a string.
The method I arrived at feels slightly hard to read:
CHROMOSOME_NUMBERS = (1..23).to_a.map { |n| n.to_s }
Is there a prettier way of doing it?
There is map method defined for Range (because Range includes Enumerable module), so you don't have to convert it manually to array:
CHROMOSOME_NUMBERS = (1..23).map(&:to_s)
('1'..'23').to_a
=> ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23"]
I've this familiar question that looks like permutation/combination of the Math world.
How can I achieve the following via ruby?
badges = "1-2-3"
badge_cascade = []
badges.split("-").each do |b|
badge_cascade << b
end
Gives: => ["1", "2", "3"]
But I want it to be is:
=> ["1", "2", "3",
"1-2", "2-3", "3-1", "2-1", "3-2", "1-3",
"1-2-3", "2-3-1", "3-1-2"]
Functional approach:
bs = "1-2-3".split("-")
strings = 1.upto(bs.size).flat_map do |n|
bs.permutation(n).map { |vs| vs.join("-") }
end
#=> ["1", "2", "3", "1-2", "1-3", "2-1", "2-3", "3-1", "3-2", "1-2-3", "1-3-2", "2-1-3", "2-3-1", "3-1-2", "3-2-1"]
You ned to use Array#permutation method in order to get all permutations:
arr = "1-2-3".split '-' # => ["1", "2", "3"]
res = (1..arr.length).reduce([]) { |res, length|
res += arr.permutation(length).to_a
}.map {|arr| arr.join('-')}
puts res.inspect
# => ["1", "2", "3", "1-2", "1-3", "2-1", "2-3", "3-1", "3-2", "1-2-3", "1-3-2", "2-1-3", "2-3-1", "3-1-2", "3-2-1"]
Let me explain the code:
You split string into array passing separator '-' to String#split method
You need all permutations of length 1, 2, 3. Range 1..arr.length represents all these lengths.
You collect an array of all permutations using Enumerable#reduce.
You will get array of arrays here:
[["1"], ["2"], ["3"], ["1", "2"], ["1", "3"], ["2", "1"], ["2", "3"], ["3", "1"], ["3", "2"], ["1", "2", "3"], ["1", "3", "2"], ["2", "1", "3"], ["2", "3", "1"], ["3", "1", "2"], ["3", "2", "1"]]
You transform all subarrays of this array into strings using Array#join with your '-' separator inside of Enumerable#map
Array#permutation(n) will give you all the permutations of length n as an Array of Arrays so you can call this with each length between 1 and the number of digits in badges. The final step is to map these all back into strings delimited with -.
badges = "1-2-3"
badges_split = badges.split('-')
permutations = []
(1..badges_split.size).each do |n|
permutations += badges_split.permutation(n).to_a
end
result = permutations.map { |permutation| permutation.join('-') }
Update: I think Alex's use of reduce is a more elegant approach but I'll leave this answer here for now in case it is useful.
I have an array of values, and an array which determines the order.
How can I quickly re-arrange the array in the given order?
data = ['0','1','2','3','4','5']
order = [3,1,2,0,4,5]
I want:
data = ['3','1','2','0','4','5']
You can use the values_at method written for this kind of task:
data = ['0','1','2','3','4','5']
order = [3,1,2,0,4,5]
data.values_at *order
# => ["3", "1", "2", "0", "4", "5"]
data = ["0", "1", "2", "3", "4", "5"]
order = [3, 1, 2, 0, 4, 5]
> order.map{|x| data[x]}
=> ["3", "1", "2", "0", "4", "5"]
If you are not sure if the indices are correct, you can do this:
> order.map{|x| data.fetch(x)} # will raise an exception if index out of bounds
=> ["3", "1", "2", "0", "4", "5"]
Not as good as #Jakub's answer using Array#values_at (which I would argue should be the accepted answer) but here are some other fun alternatives:
p data.sort_by.with_index{ |d,i| order[i] }
p data.zip(order).sort_by(&:last).map(&:first)