MongoDB 正則表達式

示例

MongoDB 使用 $regex 操作符來設置匹配字符串的正則表達式。

> db.col.find()
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bc9e64799370c0ef358c"), "x" : "nothing" }

> db.col.find({x:/world/})
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }

> db.col.find({x:{$regex:"world"}})
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }

上面后兩種操作是等價的。

不區分大小寫

> db.col.find({x:{$regex:"world", $options:"$i"}})
{ "_id" : ObjectId("56c6bd9964799370c0ef358d"), "x" : "hihi WORLD" }
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }

or

> db.col.find({x:/world/i})
{ "_id" : ObjectId("56c6bd9964799370c0ef358d"), "x" : "hihi WORLD" }
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }

數組使用正則表達式

> db.col.find({tags:/b/})
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bedf64799370c0ef358e"), "tags" : [ "abc", "m" ] }

可見數組中包含字符‘b’的都找出來了（包括“abc”）。

正則中包含變量

需要用eval將組合的字符串進行轉換

> v="world"
world

> db.col.find({x:eval("/" + v + "/i")})
{ "_id" : ObjectId("56c6bd9964799370c0ef358d"), "x" : "hihi WORLD" }
{ "_id" : ObjectId("56c6bbfe64799370c0ef358b"), "x" : "hi world", "tags" : [ "b" ] }
{ "_id" : ObjectId("56c6bbef64799370c0ef358a"), "x" : "hello world", "tags" : [ "a", "b" ] }