JSON transformer

jsontransform.py

jeffws:~/x/rawdata/20110511_intl_users$ 
jeffws:~/x/rawdata/20110511_intl_users$ cat jsontransform.py 
#!/usr/bin/python
import sys
import json

if __name__ == "__main__":
    if len(sys.argv) < 2:
      print "Usage:\n\
  Takes a file with a JSON dictionary on each line and extracts keys to a tab seperated CSV output\n\
    ex:\n\
      $ cat addresses.json id email_address tracking_id\n\
      123       [email protected]        XYZ"
    
    for line in sys.stdin:
        sys.stdout.write('\t'.join(json.loads(line)[key] for key in sys.argv[1:]) + '\n')

jeffws:~/x/rawdata/20110511_intl_users$ head -n 5 20110511_remaining_intl_users_shuffled_133.json | ./jsontransform.py field1 email
BISQBFWSQHPI2LDJXK7ULJU6QI------        [email protected]
TJDA44MYRNJ5EJC2VH2EAWOGUQ------        [email protected]
TLTHKCJTNPMJXSK5JX3VMIPM2A------        [email protected]
HIDNGS64QTHMOLNF7FEZR7735M------        [email protected]
5UZTXLLFXTEI7PEAHDGRT7WOFY------        [email protected]
jeffws:~/x/rawdata/20110511_intl_users$ head -n 5 20110511_remaining_intl_users_shuffled_133.json | ./jsontransform.py field1 email id
Traceback (most recent call last):
  File "./jsontransform.py", line 14, in <module>
    sys.stdout.write('\t'.join(json.loads(line)[key] for key in sys.argv[1:]) + '\n')
TypeError: sequence item 2: expected string or Unicode, int found
jeffws:~/x/rawdata/20110511_intl_users$ head -n 5 20110511_remaining_intl_users_shuffled_133.json | ./jsontransform.py field1 email id1
Traceback (most recent call last):
  File "./jsontransform.py", line 14, in <module>
    sys.stdout.write('\t'.join(json.loads(line)[key] for key in sys.argv[1:]) + '\n')
  File "./jsontransform.py", line 14, in <genexpr>
    sys.stdout.write('\t'.join(json.loads(line)[key] for key in sys.argv[1:]) + '\n')
KeyError: 'id1'
jeffws:~/x/rawdata/20110511_intl_users$