extract from json

[teddybubu at gmail.com]

On Friday, March 7, 2014 3:05:15 PM UTC-6, Kev Dwyer wrote:
>  wrote:
> > I can't find any example on how to do this.
> 
> > I have a json file like so:
> 
> > {"bostock":[{"url":"http://bl.ocks.org/mbostock/9360565","title":"titleplaceholder","date":"dateplaceholder"},{"url":"http://bl.ocks.org/mbostock/9265674","title":"titleplaceholder","date":"dateplaceholder"},{"url":"http://bl.ocks.org/mbostock/9265467","title":"titleplaceholder","date":"dateplaceholder"},{"url":"http://bl.ocks.org/mbostock/9234731","title":"titleplaceholder","date":"dateplaceholder"},{"url":"http://bl.ocks.org/mbostock/9232962","title":"titleplaceholder","date":"dateplaceholder"},
> > this goes on for more than 700 entries. only thing unique is the number at
> 
> > the end of the url. I am going to load the url in python, get the date and
> 
> > title and write it in the json itself. Right now I am stuck on just
> 
> > reading the url in the json. Here is my code:
> > import json
> > with open("bostock.json") as json_file:
> 
> >     json_data = json.load(json_file)
> 
> >     print(json_data)
> > I have tried json_data[0], json_data.url and a few others I forget right
> 
> > now and it does not seem to work.
> > I have already figured out how to get the title and date.
> 
> > First things first: How can i just get the url for each line of the above
> 
> > json file?
> Hello 
> Try:
> 
> Python 2.7.2 (default, Aug 19 2011, 20:41:43) [GCC] on linux2                                                           
> 
> Type "help", "copyright", "credits" or "license" for more information.                                                  

> >>> import  json
> 
> >>> with open('/tmp/bostock.json') as f:
> 
> ...     json_data = json.load(f)
> >>> json_data
> {u'bostock': [{u'url': u'http://bl.ocks.org/mbostock/9360565', u'date': 
> u'dateplaceholder', u'title': u'titleplaceholder'}, {u'url': 
> u'http://bl.ocks.org/mbostock/9265674', u'date': u'dateplaceholder', 
> u'title': u'titleplaceholder'}, {u'url': 
> u'http://bl.ocks.org/mbostock/9265467', u'date': u'dateplaceholder', 
> 
> u'title': u'titleplaceholder'}, {u'url': 
> 
> u'http://bl.ocks.org/mbostock/9234731', u'date': u'dateplaceholder', 
> u'title': u'titleplaceholder'}, {u'url': 
> u'http://bl.ocks.org/mbostock/9232962', u'date': u'dateplaceholder', 
> u'title': u'titleplaceholder'}]} 
> >>> urls = [x['url'] for x in json_data['bostock']]
> 
> >>> urls
> 
> [u'http://bl.ocks.org/mbostock/9360565', 
> 
> u'http://bl.ocks.org/mbostock/9265674', 
> 
> u'http://bl.ocks.org/mbostock/9265467', 
> 
> u'http://bl.ocks.org/mbostock/9234731', 

> u'http://bl.ocks.org/mbostock/9232962']
 
> Python loads the json in the file into a dictionary.  In this case, the 
> dictionary has a single key, 'bostock', and the value in the dictionary for 
 
> that key is a list (of dictionaries).  

> To get the urls, you need to get the list 
 
> json_data['bostock']
>  and then iterate over it's elements, getting the value for the key url for 
 > each one.  
> This is what the list comprehension 
> [x['url'] for x in json_data['bostock']]
> does.
> I hope that helps, 
> Kev

Kev your the man. Thanks