Question

I’m pretty new to Python, so I’m having a hard time even coming up with the proper jargon to describe my issue.
Basic idea is I have a dict that has the following structure:

myDict = 
"SomeMetric":{
    "day":[
        {"date": "2013-01-01","value": 1234},
        {"date": "2013-01-02","value": 5678},
        etc...

I want to pull out the “value” where the date is known. So I want:

myDict["SomeMetric"]["day"]["value"] where myDict["SomeMetric"]["day"]["date"] = "2013-01-02"

Is there a nice one-line method for this without iterating through the whole dict as my dict is much larger, and I’m already iterating through it, so I’d rather not do nested iteritems.

Answer 1

Generator expressions to the resque:

next(d['value']
    for d in myDict['SomeMetric']['day']
    if d['date'] == "2013-01-02")

So, loop over all day dictionaries, and find the first one that matches the date you are looking for. This loop stops as soon as a match is found.