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POHow to make projections of selected attributes in mongoid?
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  1. POHow to make projections of selected attributes in mongoid?
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    copied!<p>I have Coordinate model with many markers embedded_in User model. How to extract attributes without _ids so that on output display only each lng and lat?</p> <p>structure:</p> <pre><code>{ "_id" : ObjectId( "4e9f418f1e7bf20fbc000009" ), "name" : "test", "coordinates" : [ { "lng" : 16.86783310009764, "lat" : 52.38353842845282, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000a" ) }, { "lng" : 16.85787674023436, "lat" : 52.40972501601293, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000b" ) }, { "lng" : 16.92276474072264, "lat" : 52.40071858320756, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000c" ) }, { "lng" : 16.90182205273436, "lat" : 52.38270020105396, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000d" ) }, { "lng" : 16.96705337597655, "lat" : 52.410661698108, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000e" ) }, { "lng" : 16.89495559765624, "lat" : 52.42773236584494, "_id" : ObjectId( "4e9f418f1e7bf20fbc00000f" ) } ] } </code></pre> <p>e.g.</p> <pre><code>= debug @user.coordinates.to_json </code></pre> <p>gives:</p> <pre><code>--- ! '[{"_id":"4e9f418f1e7bf20fbc00000a","lat":52.383538428452816,"lng":16.86783310009764},{"_id":"4e9f418f1e7bf20fbc00000b","lat":52.40972501601293,"lng":16.85787674023436},{"_id":"4e9f418f1e7bf20fbc00000c","lat":52.40071858320756,"lng":16.92276474072264},{"_id":"4e9f418f1e7bf20fbc00000d","lat":52.382700201053964,"lng":16.90182205273436},{"_id":"4e9f418f1e7bf20fbc00000e","lat":52.410661698108,"lng":16.967053375976548},{"_id":"4e9f418f1e7bf20fbc00000f","lat":52.42773236584494,"lng":16.894955597656235}]' </code></pre> <p>expected:</p> <pre><code>--- ! '[{"lat":52.383538428452816,"lng":16.86783310009764},{"lat":52.40972501601293,"lng":16.85787674023436},{"lat":52.40071858320756,"lng":16.92276474072264},{"lat":52.382700201053964,"lng":16.90182205273436},{"lat":52.410661698108,"lng":16.967053375976548},{"lat":52.42773236584494,"lng":16.894955597656235}]' </code></pre>
 

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