Filter list of dictionaries

Question

This is my example:

dictlist = [{\'first\': \'James\', \'last\': \'Joule\'}, 
            {\'first\': \'James\',\'last\': \'Watt\'},
            {\'first\':          


        

Answer 1

This is very simple solution with list comprehension:

>>> dictlist = [{'first': 'James', 'last': 'Joule'}, {'first': 'James','last': 'Watt'},{'first': 'Christian','last': 'Doppler'}]
>>> [x['last'] for x in dictlist if x['first'] == 'Christian']
['Doppler']

Answer 2

for comp in dictlist:
    if comp["first"] == 'Christian':
        return comp["last"]

Answer 3

I sometimes like to use next:

next((d['last'] for d in dictlist if d['first'] == 'Christian'), None)
# 'Doppler'

The first argument is an iterator and the second (optional) argument is the default value returned if no matching entry is found.

Note: this will only return the first matching result. So it wouldn't be good if you expect to have multiple records matching your "query".

Answer 4

dictlist = [{'first': 'James', 'last': 'Joule'}, {'first': 'James','last': 'Watt'},{'first': 'Christian','last': 'Doppler'}]
the_jameses = [d for d in dictlist if d['first'] == 'James']

Where the resulting list contains only:

[{'first': 'James', 'last': 'Joule'}, {'first': 'James', 'last': 'Watt'}]

Answer 5

Something like this should work

last_name = ''

for d in dictList:
  if d['first'] == 'Christian':
    last_name = d['last']
    break