python - How to convert a csv file, that has array data, into a json file? -

i have csv file bunch of columns. few of columns same, want convert them json object live under same array.

for example in csv:

firstname,lastname,pet,pet,pet joe, dimaggio, dog, cat pete, rose, turtle, cat jackie, robinson, dog 

i want json be

{ firstname: joe,   lastname: dimaggio,   pets: ["dog", "cat"] }, { firstname: pete,   lastname: rose,   pets: ["turtle", "cat"] }, { firstname: jackie,   lastname: robinson,   pets: ["dog"] } 

i'm trying write simple python script i'm running problems.

here's i've got far:

import csv import json  csvfile = open('userdata.csv', 'r') jsonfile = open('userdata.json', 'w')  fieldnames = ("firstname", "lastname", "pet", "pet", "pet"); reader = csv.dictreader( csvfile, fieldnames) record = {} row in reader:     record['firstname'] = row['firstname']     record['lastname'] = row['lastname']     record['pets'] = json.jsonencoder().encode({"pets": [row['pet'], row['pet'], row['pet'], row['pet'], row['pet']]});     json.dump(record, jsonfile, indent=4)     ##json.dump(json.loads(json.jsonencoder(record)), jsonfile, indent=4) print "something worked" 

but acting funny since it's printing pets array inside object called pets.

i can't figure out how array pets outside object `pets. it's adding backslashes array items

{     "firstname": "joe",     "lastname": "dimaggio",      "pets": "{\"pets\": [\"dog\", \"cat\"]}" } 

it because encoding , using json.dumps encoding twice. remove json.jsonencoder().encode(...) , should work correctly.

import csv import json  csvfile = open('userdata.csv', 'r') jsonfile = open('userdata.json', 'w')  fieldnames = ("firstname", "lastname", "pet", "pet", "pet"); reader = csv.dictreader( csvfile, fieldnames) record = {} row in reader:     record['firstname'] = row['firstname']     record['lastname'] = row['lastname']     record['pets'] = [[row['pet'], row['pet'], row['pet'], row['pet'], row['pet']]     # remove blank entries     record['pets'] = [x x in record['pets'] if x not '']     json.dumps(record, jsonfile, indent=4) print "something worked" 

the backslashes saw escaping json string, result of serializing twice.