[{"_id":{"$oid":"637ac16a7c31adec64511551"},"User":"0","Card":"0","Year":"2002","Month":"11","Day":"26","Time":"11:21","Amount":"$379.73","Use Chip":"Swipe Transaction","Merchant Name":"6515854639642454768","Merchant City":"Calexico","Merchant State":"CA","Zip":"92231.0","MCC":"3066","Errors?":"","Is Fraud?":"No"}]

db.collection.aggregate([{"$project":{"MCC":1,"cost_split":{"$split":["$Amount",{$literal:"$"}]}}}])