Ruby sort_by 哈希数组

Question

我有一个哈希数组，我希望能够按其中一个值的字母顺序对其进行排序。

哈希数组：

[{"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"}]

运行sort_by之后：

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"}]

它对 field_int 列进行了正确排序，但我不明白为什么它对 field_string 列无法正常工作。如果有人有任何想法，我会很高兴听到他们。

谢谢！

Answer 1

哈希中的键是字符串而不是符号。

records[0][:field_string] 是 nil

records[0]["field_string"] 是 "test"

因此您的排序是将 nils 与 nils 进行比较，并保持原始顺序。

你需要：

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

它输出：

=> [{"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"}]

可能会造成混淆，因为 HashWithIndifferentAccess 也存在。

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