Ruby Array collect 怎么用？
@sco_array = [#<ExaminationScore:0x10051fe0 @attributes={"student_id"=>"1951", "subject_id"=>"3", "student_name"=>"qqq", "subject_title"=>"英语", "student_code"=>"3101012001320100119", "score"=>"0", "clazz_name"=>"高三(10)班"}>]
想得到 title 是英文的分数，用学生 id 做键，分数做值，怎么实现？
@scores.collect { |s| s.subject_title == '英语' }
请教各位
hash_result = {}
@scores.select { |s| s.subject_title == '英语' }.collect { |s| hash_result[s.student_id] = s.score }
这样是否就满足你的需求了，光一个 collect 搞不定吧？
可以用 Hash[] 把数组转换为 Hash。
Hash[@scores.select { |x| x.subject_title == '英语‘ }.collect { |x| [x.student_id, x.score] }]
传统一点的办法就是用 each 遍历数组时赋值给 hash，我个人倾向于下面这种
hash = {}
@scores.each { |x| hash[x.student_id] = x.score if x.subject_title == '英语' }
@sco_array.inject({}) do |hash, score|
hash[score.student_id] = score.score if score.subject_title == '英语'
hash
end
@sco_array.inject({}) do |hash, score|
hash[score.student_id] = score.score if score.subject_title == '英语'
end
我记得可以这样吧~