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MongoDB/PHP/MapReduce/Reg Exp/Strings->Floats

mapreduce mongodb php

0

Ben Coffin · 技术社区 · 7 年前

我是MapReduce的新手,但我有一个收藏,我想利用它来学习MapReduce的工作原理。

示例文件:

{ "filename" : "resume.doc",
  "folder"   : "work",
  "completed": "0.5" },

{ "filename" : "spreadsheet.xls",
  "folder"   : "work",
  "completed": "0.6" },

{ "filename" : "thesis.doc",
  "folder"   : "school",
  "completed": "0.75" },

{ "filename" : "coverletter.doc",
  "folder"   : "work",
  "completed": "0.6"}

所以整个想法是:我想问:

{ "folder"   : "work", 
  "completed": { $gt: 0.5 }, 
  "filename" : new MongoRegex( "/\.[a-zA-Z]{2,}$/" ) }

{ ".doc" : 1,
  ".xls" : 1 }

我还意识到我遇到了一个问题,因为我的代码是字符串,而不是浮点数,所以我认为mongodb需要更多的指令来比较字符串。

我正在使用(如果重要的话):

PHP extension: mongo/1.5.7
MongoDB: version 3.2.11

1 回复 | 直到 7 年前

1

0

Ben Coffin 7 年前

似乎我偶然发现了自己的答案。如果有人提出更简洁/专业的解决方案,请告诉我。

try {

$map = new MongoCode(

    'function(){ 
        var re = new RegExp(/(.+)\.([a-zA-Z]{2,})$/);
        doctype = this.value.match(re);
        if(parseFloat(this.completed)>0.5){
            emit(doctype[2], parseFloat(this.completed));
        }
    }'

);

$reduce = new MongoCode(

    'function(key, values){ 
        var sum = 0, num = 0;
        for(var i in values){
            if(parseFloat(values[i])>0.5){
                sum += values[i];
                num += 1;
            }
        }
        return { number_of_documents :         num, 
                 sum_of_document_completions : sum, 
                 average_completion :          (sum/num) }; 
    }'

);

$query = array (
        "folder"    => "work"
);

$doctypes = $db->command( 
        array(
            'mapReduce'     => 'mydocuments',
            "map"           => $map,
            "reduce"        => $reduce,
            "query"         => $query,
            "out"           => array("inline"=>1)
        )
);

print_r ( $doctypes);

}
catch(MongoCursorException $e) {
     echo "error message: ".$e->getMessage()."\n";
     echo "error code: ".$e->getCode()."\n";
}