Counting number of lines in a JSON file using Python

Question

I have a .json file which contains a JSON item on every line. I want to try and count how many JSON items I have within the file using Python. I am currently just counting the lines using the following code

count =0
with open(file) as f:
    for line in f:
        count+=1

This seems like an unefficient way of doing it though. Is there a more efficient way of either calculating the number of JSON items in a .json file or counting the number of lines within a file?

Lampshady · Accepted Answer · 2014-03-04T18:05:35.153

3

Edit to fix my wrong doing:

This is a one liner for counting lines in file.

num = sum(1 for line in open(filename))

edited Mar 04 '14 at 18:05

answered Mar 04 '14 at 17:35

Lampshady

102
4

This assumes that the *JSON items* the OP is using are JSON objects with just one key.. The OP is counting *lines* here instead. – Martijn Pieters Mar 04 '14 at 17:38
Why do you think reading and scanning a line would be quicker than just reading a line? The OP specified that each line is a distinct JSON item so there should be no need to check for that. – tripleee Mar 04 '14 at 17:38
How do you know that `":"` isn't a substring of an element? – DSM Mar 04 '14 at 17:41
Apologies, will delete shortly. – Lampshady Mar 04 '14 at 17:48

Counting number of lines in a JSON file using Python

1 Answers1