注：作者使用的MongoDB為2.4.7版本。

單詞計數(shù)示例：

插入用于單詞計數(shù)的數(shù)據(jù)：

db.data.insert({sentence:’Consider the following map-reduce operations on a collection orders that contains documents of the following prototype’})
db.data.insert({sentence:’I get the following error when I follow the code found in this link’})