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Array#insert_every(skip, elem)
An insert_every method for Ruby arrays.
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class Array | |
def insert_every!(skip, str) | |
orig_ary_length = self.length | |
new_ary_length = orig_ary_length + ((orig_ary_length-1) / skip) | |
i = skip | |
while(i<new_ary_length) do self.insert(i,str); i+=(skip+1) end | |
self | |
end | |
end | |
# a recursive version which is a little cleaner/more elegant: | |
class Array | |
def insert_every!(skip, str, from=0, to=self.length) | |
insert_every!(skip, str, from+skip, to) if from < to | |
insert(from,str) unless from==0 || from==to | |
self | |
end | |
end | |
p %w[ 1 2 3 4 5 6 7 8 9 10 11 12 ].insert_every!(3, ',') | |
#=> ["1", "2", "3", ",", "4", "5", "6", ",", "7", "8", "9", ",", "10", "11", "12"] | |
# Spooner's version using range stepping | |
class Array | |
def insert_every!(skip, str) | |
(skip...size).step(skip).with_index {|n, i| insert(n + i, str) } | |
self | |
end | |
end | |
p %w[ 1 2 3 4 5 6 7 8 9 10 11 12 ].insert_every!(3, ',') | |
#=> ["1", "2", "3", ",", "4", "5", "6", ",", "7", "8", "9", ",", "10", "11", "12"] |
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