R Data Analysis Cookbook, Second Edition - Second Edition

Find most severe crime zone

The aggregate() function allows you to run an aggregation pipeline. For example the following pipeline calculates the total crimes per location and then shows it using a horizontal bar plot which is shown in the graph after the code:

> library(ggplot2) 
> crime_collection$aggregate('[{"$group":{"_id":"$LocationDescription", "Count": {"$sum":1}}}]')%>%na.omit()%>%arrange(desc(Count))%>%head(10)%>%ggplot(aes(x=reorder(`_id`,Count),y=Count))+geom_bar(stat="identity",fill='#c37600')+geom_text(aes(label = Count), color = "blue") +coord_flip()+xlab("Location Description")