Ruby sort_by 哈希數組

Question

我有一個哈希數組，我希望能夠按字母順序對其中一個值進行排序。

哈希數組：

[{"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>22, "field_string"=>"c next"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>33, "field_string"=>"d next"}]

運行 sort_by 后：

records.sort_by { |rec| rec[:field_string]}
=> [{"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>22, "field_string"=>"c next"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>33, "field_string"=>"d next"}]

它為 field_int 列正確排序，但我不明白為什么它不能與 field_string 一起正常工作。 如果有人有任何想法，我會非常感激聽到他們的聲音。

謝謝！

Answer 1

哈希中的鍵是字符串而不是符號。

records[0][:field_string] nil

records[0]["field_string"]是"test"

因此，您的排序是將 nils 與 nils 進行比較，並保持原始順序。

你需要：

records.sort_by { |rec| rec["field_string"]}

它輸出：

=> [{"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"batch update testing"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>22, "field_string"=>"c next"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>33, "field_string"=>"d next"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"},
 {"hidden"=>false, "id"=>"5f898f7784743992f24fcb51", "field_int"=>11, "field_string"=>"test"}]

這可能會令人困惑，因為HashWithIndifferentAccess也存在。