Question

我很难从iOS应用发送的字符串中提取ID和Answer值。在以下示例中，我有四个ID和四个需要提取的答案。

s = "ID:1_Answer1_ID:2_Answer2_ID:3_AnswerRandom_ID:789_Answer3.5"

IDs_array = [1,2,3,789]
Answers_array = [Answer1,Answer2,AnswerRandom,Answer3.5]

感谢任何帮助或建议。

Answer 1

ids, answers = s.scan(/ID:(\d+)_([^_]+)/).transpose

正则表达式的想法是：

ID> 前面有 ID： - ID:
实际的 ID 是数字 - (\d+)
它们与带有下划线的答案分开 - _
答案本身是一系列非下划线字符([^_]+)

String#scan带有对数组[id, answer]的返回数组，因此我们将其转置为两个数组 - 一个带有 ids ，另一个带有答案。然后我们使用多个赋值来解压外部数组。

Answer 2

没有正则表达式，我的主张：

i = 0
names = []
ids = []
s = "ID:1_Answer1_ID:2_Answer2_ID:3_AnswerRandom_ID:789_Answer3.5"

s.split("_").each do |f|
    if i.odd?
        names.push(f)
    else
        ids.push(f.split(":")[1])       
    end
    i+=1
end

Answer 3

有很多方法可以做到这一点。这是一个使用两个连续的split并且没有正则表达式的。我假设字符串开始ID:，因为如果不一定是这种情况，则需要进一步说明问题。

ids, answers = s[3..-1].split(/_ID:/).map { |str| str.split('_') }.transpose
  #=> [["1", "2", "3", "789"],
  #    ["Answer1", "Answer2", "AnswerRandom", "Answer3.5"]]

步骤：

t = s[3..-1]
  #=> "1_Answer1_ID:2_Answer2_ID:3_AnswerRandom_ID:789_Answer3.5" 
a = t.split('_ID:')
  #=> ["1_Answer1", "2_Answer2", "3_AnswerRandom", "789_Answer3.5"] 
b = a.map { |str| str.split('_') }
  #=> [["1", "Answer1"], ["2", "Answer2"],
  #    ["3", "AnswerRandom"], ["789", "Answer3.5"]] 
b.transpose
  #=> [["1", "2", "3", "789"],
  #    ["Answer1", "Answer2", "AnswerRandom", "Answer3.5"]]

Answer 4

请澄清你的问题。

ID和答案是否需要匹配？他们总是成双成对的？ "_"字符是否总是用作分隔符（这意味着应该对答案进行编码）？格式总是：

"ID:#{id_mumber}_#{answer in text}" ... "_" ... *

我会假设我问的所有问题的答案是＆＃34;是＆＃34;，但如果我错了，请编辑你的问题并留下评论 - 我将编辑答案。

s = "ID:1_Answer1_ID:2_Answer2_ID:3_AnswerRandom_ID:789_Answer3.5"

answer_hash = {}

tmp = s.split('_')

answer_hash[tmp.shift[3..-1].to_i] = tmp.shift while tmp[0]

answer_hash # => {1=>"Answer1", 2=>"Answer2", 3=>"AnswerRandom", 789=>"Answer3.5"} 
answer_hash.keys # => [1, 2, 3, 789]
answer_hash.values # => ["Answer1", "Answer2", "AnswerRandom", "Answer3.5"]

修改

我喜欢@ndn使用Regexp的答案......它更清晰，但对于较短的字符串可能会更慢。

以下是我的机器上的基准测试 - 它们表明性能差异主要是针对较短的ID字符串：

s = "ID:1_Answer1_ID:2_Answer2_ID:3_AnswerRandom_ID:789_Answer3.5" puts Benchmark.measure {100_000.times {answer_hash = {}; tmp = s.split('_'); answer_hash[tmp.shift[3..-1].to_i] = tmp.shift while tmp[0] } } # ### Short string using str # => 0.280000 0.000000 0.280000 ( 0.286917) puts Benchmark.measure {100_000.times {ids, answers = *s.scan(/(?<=ID:)(\d+)_([^_]+)/).transpose } } # ### Short string using string.scan Regexp # => 0.590000 0.000000 0.590000 ( 0.595052) s = [] 100.times {|i| s << ("ID:#{i}_Answer#{i}") } s = s.join('_') puts Benchmark.measure {100_000.times {answer_hash = {}; tmp = s.split('_'); answer_hash[tmp.shift[3..-1].to_i] = tmp.shift while tmp[0] } } # ### Medium string using string.split # => 7.180000 0.010000 7.190000 ( 7.213266) puts Benchmark.measure {100_000.times {ids, answers = *s.scan(/(?<=ID:)(\d+)_([^_]+)/).transpose } } # ### Medium string using string.scan Regexp # => 8.860000 0.020000 8.880000 ( 8.888352) s = [] 1000.times {|i| s << ("ID:#{i}_Answer#{i}") } s = s.join('_') puts Benchmark.measure {1000.times {answer_hash = {}; tmp = s.split('_'); answer_hash[tmp.shift[3..-1].to_i] = tmp.shift while tmp[0] } } # ### Long string using string.split (shorter benchmark) # => 0.690000 0.000000 0.690000 ( 0.693698) puts Benchmark.measure {1000.times {ids, answers = *s.scan(/(?<=ID:)(\d+)_([^_]+)/).transpose } } # ### Long string using string.scan Regexp (shorter benchmark) # => 0.900000 0.000000 0.900000 ( 0.901358)

从长字符串中提取值

4 个答案: