I am trying to turn this string
"a,bc,c"
into this array..
["a", "b", "c"]
I've used split on the comma & iterated through it but I'd like to find a cleaner way.
Thanks!
I will use #scan and #uniq method.
"a, bc,c".scan(/[a-z]/).uniq
# => ["a", "b", "c"]
Here we go, one option:
"a, bc,c".gsub(/\W+/, '').chars.uniq
# Outputs:
=> ["a", "b", "c"]
Related
I need to reorganize an array into slices of 2 elements and then sort each slice alphabetically using each_slice
I've managed to get the each_slice correctly but I can seem to then sort each sub array.
What am I doing wrong here?
array.each_slice(2).to_a { |el| el = el.sort}
You just need to create a new array with the output that you want.
For instance:
# $ array = ["b", "a", "d", "c", "k", "l", "p"]
arr = []
array.each_slice(2) { |el| arr << el.sort}
# $ arr
# => [["a", "b"], ["c", "d"], ["k", "l"], ["p"]]
EDIT:
Pointed in the comments (by #mu is too short), you can also do:
arr = array.each_slice(2).map(&:sort)
In Ruby, how do I split a string and not keep the delimiter in the resulting split array? I though tthis was the default, but when I try
2.4.0 :016 > str = "a b c"
=> "a b c"
2.4.0 :017 > str.split(/([[:space:]]|,)+/)
=> ["a", " ", "b", " ", "c"]
I see the spaces included in my result. I would like the result to simply be
["a", "b", "c"]
From the String#split documentation:
If pattern contains groups, the respective matches will be returned in the array as well.
Answering your explicitly stated question: do not match the group:
# ⇓⇓ HERE
str.split(/(?:[[:space:]]|,)+/)
or, even without groups:
str.split(/[[:space:],]+/)
or, in more Rubyish way:
'a b, c,d e'.split(/[\p{Space},]+/)
#⇒ ["a", "b", "c", "d", "e"]
String#splitsplits on white-space by default, so don 't bother with a regex:
"a b c".split # => ["a", "b", "c"]
Try this please
str.split(' ')
With Ruby how do I split on either one of tow conditions -- wheter there are 3 or more spaces or a tab charadter? I tried this
2.4.0 :003 > line = "a\tb\tc"
=> "a\tb\tc"
2.4.0 :004 > line.split(/([[:space:]][[:space:]][[:space:]]+|\t)/)
=> ["a", "\t", "b", "\t", "c"]
but as you can see, the tab character itself is getting included in my results. The results should be
["a", "b", "c"]
What about just split?
p "a\tb\tc".split
# ["a", "b", "c"]
p "a\tb\tc\t\tc\t\t\t\t\t\t\tc\ts\ts\tt".split
# ["a", "b", "c", "c", "c", "s", "s", "t"]
Although that doesn't split when there are three 3 or more white spaces, this might work:
p "a\tb\tc\t\tc\t\t\ t\t\tc\ts\ts\tt".split(/\s{3,}|\t/)
# => ["a", "b", "c", "c", "t", "c", "s", "s", "t"]
line = "aa bb cc\tdd"
line.split /\p{Space}{3,}|\t+/
#⇒ ["aa bb", "cc", "dd"]
I'm fairly new to ruby and it's my first question here on stackoverflow so pardon me if I'm being a complete noob.
The code which i am working with contains this line -
puts (6..6).flat_map{|n| ('a'..'z').to_a.combination(n).map(&:join)}
What the code does is that its starts printing each of the combinations starting from "abcdef" and continues till the end (which i have never seen as it has 26^6 combinations).
Of course having an array of that size (26^6) is unimaginable hence I was wondering if there is any way by which i can get next combination in a variable, work with it, and then continue on to the next combination ?
For example I calculate the first combination as "abcdef" and store it in a variable 'combo' and use that variable somewhere and then the next combination is calculated and "abcdeg" is stored in 'combo' and hence the loop continues ?
Thanks
(6..6).flat_map { |n| ... } doesn't do much. Your code is equivalent to:
puts ('a'..'z').to_a.combination(6).map(&:join)
To process the values one by one, you can pass a block to combination:
('a'..'z').to_a.combination(6) do |combo|
puts combo.join
end
If no block is given, combination returns an Enumerator that can be iterated by calling next:
enum = ('a'..'z').to_a.combination(6)
#=> #<Enumerator: ["a", "b", "c", ..., "w", "x", "y", "z"]:combination(6)>
enum.next
#=> ["a", "b", "c", "d", "e", "f"]
enum.next
#=> ["a", "b", "c", "d", "e", "g"]
enum.next
#=> ["a", "b", "c", "d", "e", "h"]
Note that ('a'..'z').to_a.combination(6) will "only" yield 230,230 combinations:
('a'..'z').to_a.combination(6).size
#=> 230230
As opposed to 26 ^ 6 = 308,915,776. You are probably looking for repeated_permutation:
('a'..'z').to_a.repeated_permutation(6).size
#=> 308915776
Another way to iterate from "aaaaaa" to "zzzzzz" is a simple range:
('aaaaaa'..'zzzzzz').each do |combo|
puts combo
end
Or manually by calling String#succ: (this is what Range#each does under the hood)
'aaaaaa'.succ #=> "aaaaab"
'aaaaab'.succ #=> "aaaaac"
'aaaaaz'.succ #=> "aaaaba"
I have the following arrays:
passing_grades = ["A", "B", "C", "D"]
student2434 = ["F", "A", "C", "C", "B"]
and I need to verify that all elements in the student array are included in the passing_grades array. In the scenario above, student2434 would return false. But this student:
student777 = ["C", "A", "C", "C", "B"]
would return true. I tried something like:
if student777.include? passing_grades then return true else return false end
without success. Any help is appreciated.
PASSING_GRADES = ["A", "B", "C", "D"]
def passed?(grades)
(grades - PASSING_GRADES).empty?
end
similar to what CDub had but without bug. more readable in my opinion
You could have a method that does the difference of the arrays, and if any results are present, they didn't pass:
PASSING_GRADES = ["A", "B", "C", "D"]
def passed?(grades)
grades.all? {|grade| PASSING_GRADES.include?(grade)}
end
Example:
1.9.3-p484 :117 > student777 = ["C", "A", "C", "C", "B"]
=> ["C", "A", "C", "C", "B"]
1.9.3-p484 :118 > passed?(student777)
=> true
1.9.3-p484 :118 > passed?(student2434)
=> false