How does Mongodb delete databases with specified conditions in batches?

Question

For example, I have 1,000 databases and want to delete all databases starting with a. How do I do this?
(note database not collection)

Answer 1

It requires a little skill, but it’s not troublesome, just a script:

db.runCommand({listDatabases: 1}).databases.forEach(function(database) {
    if(database.name.match(/^a/)) {
        db.getDB(database.name).dropDatabase();
    }
});

Probably just pass listDatabase得到所有的库，然后从中找到符合你条件的库，然后dropDatabase()删除掉。
注意避开关键的系统库，比如local, config, admin and wait