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[英]Function is not recognized in map reduce command, mongoDB (javascript)
[英]Map reduce mongodb javascript IGNORE NULL values in this
我不确定如何,但我想在this.tag_list
为空时继续
var mapFunc3 = function(){
var tags = this.tag_list.split(',');
for (i in tags) {
emit(tags[i], 1);
}
}
var reducFunc3 = function(key, values){
var count = 0;
for( i in values){
count += values[i];
}
return count;
}
db.names.mapReduce(
mapFunc3,
reducFunc3,
{out: "mr_3"}
)
我得到的错误是:
"errmsg" : "MapReduce internal error :: caused by :: TypeError: this.tag_list is null :\n@:2:5\n",
"code" : 139,
"codeName" : "JSInterpreterFailure"
}
因此,我没有更改 JavaScript,而是更改了 Mongodb 查询,使其不映射任何空项:
db.names.mapReduce(
mapFunc3,
reducFunc3,
{
out: {merge: "mr_3"},
query: {"tag_list": {$ne: null}}
}
)
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