给定一个包含字符串索引的序列,
str_indices = [[1,2],[7,8]],
如何最好地从字符串中排除这些字符?
例如,给定上述标记为排除的索引和字符串happydays
,希望返回hpyda
。
使用范围:
str_indices=[[1,2],[7,8]]
str="happydays"
str_indices.reverse.each{|a| str[Range.new(*a)]=''}
str
=> "hpyda"
如果您不想修改原始内容:
str_indices.reverse.inject(str){|s,a|(c=s.dup)[Range.new(*a)]='';c}
猜测这是最好的做法。
str_indices = str_indices.flatten.reverse
string = "happydays"
str_indices.each{|i| string[i]=""}
对于 Ruby 1.9,
string = 'happydays'
[-1, *str_indices.flatten(1), 0].each_slice(2).map{|i, j| string[i+1..j-1]}.join
对于 Ruby 1.8,请在此之前写入 require 'enumerator'
。
[[1,2],[7,8]].reverse.inject('happydays') { |m, (f,l)| m[f..l] = ''; m }
以下内容不要求str_indices
所标识的范围是非重叠或以任何方式排序的。
str_indices = [[4,6], [1,2], [11,12], [9,11]]
str = "whatchamacallit"
keeper_indices = str.size.times.to_a -
str_indices.reduce([]) { |a,(from,to)| a | (from..to).to_a }
# => [0, 3, 7, 8, 13, 14]
str.chars.values_at(*keeper_indices).join
#=> "wtmait"
只是为了好玩 :)
str_indices = [[1,2],[7,8]]
str = "happydays"
str_indices.flatten.reverse.inject(str.split("")){|a,i| a.delete_at i; a}.join
#=> hpyda
str = "happydays"
indexes_to_reject = [[1,7],[2,8]] # Not in "correct" order, but still works
all_indexes = indexes_to_reject.flatten(1)
str.each_char.reject.with_index{|char, index| all_indexes.include?(index)}.join
它还可以与范围一起使用:
str = "happydays"
ranges_to_reject = [1..2, 7..8]
str.chars.reject.with_index {|char, index|
ranges_to_reject.any?{|range| range.include?(index)}
}.join
[(1..2), (7..8), (10..20)]
- fl00r