regular expression to filter out part of key value in a json string

Question

I have the following JSON string as part of a log line.

cells : {"Lac":"7824","CntryISO":"us","NetTyp":"GSM","NetOp":"310260","Cid":"11983"}

I want to filter out to the following format: {"Lac":"7824","Cid":"11983"}.

How can do this using regular expression ? in Javascript or Python ? the keys are constant strings(Lac, CntryISO, ...), but the value strings are varying.

except that using regexen to parse JSON is even more retarded than using them to parse XML because JSON is so much easier to work with correctly. — aaronasterling
– aaronasterling, Commented Nov 12, 2010 at 2:46
For those who think this is retarded question...This is from the log text I got from the server...I know I can easily re-construct the json object and manipulate it...however, it is just too much overhead to create a json for each log line for this....I believe reg exp should be able to handle it.. — haijin
– haijin, Commented Nov 13, 2010 at 21:34

alex · Accepted Answer · 2010-11-12 01:59:35Z

5

Why don't you just delete them in JavaScript?

var myJson = {"Lac":"7824","CntryISO":"us","NetTyp":"GSM","NetOp":"310260","Cid":"11983"};

delete myJson.Lac;
delete myJson.cId;

answered Nov 12, 2010 at 1:59

alex

492k205 gold badges891 silver badges992 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

haijin Over a year ago

why can't reg exp handle this ? it should not be that hard...I hate to create a json object for each log line and let GC run constantly.

nonot1 · Accepted Answer · 2010-11-12 03:22:42Z

1

To expand and explain @alex answer:

JSON is a nested multi dimensional structure. Simply filtering the "string-ifiyed form of a Javascript object" (aka JSON) will work in very simple cases, but will rapidly fail when the structure is no longer flat or it starts to get complex with escaped fields, etc.

At that point you will need proper parsing logic. This is nicely supplied by Javascript itself, to quote @alexes code:

var myJson = {"Lac":"7824","CntryISO":"us","NetTyp":"GSM","NetOp":"310260","Cid":"11983"};

delete myJson.Lac;
delete myJson.cId;

Or, if you want to use python, the json module will work just fine: http://docs.python.org/library/json.html

Good luck! :)

answered Nov 12, 2010 at 3:22

nonot1

2,8284 gold badges27 silver badges42 bronze badges

Comments

Wenxiang Wu · Accepted Answer · 2010-11-12 02:41:24Z

0

Why would you want to use regex for this when you can just use a JSON parser/serializer? Try cjson in Python if you are concerned about speed, it is faster than 'json' module in the Python standard library.

answered Nov 12, 2010 at 2:41

Wenxiang Wu

931 silver badge6 bronze badges

1 Comment

haijin Over a year ago

I can...but entail the overhead of creating json object for each log line...I am just wondering this should not be hard with reg exp...maybe I am wrong.

Collectives™ on Stack Overflow

regular expression to filter out part of key value in a json string

3 Answers 3

1 Comment

Comments

1 Comment

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Linked

Related