python filter list of dictionaries based on key value

Question

I have a list of dictionaries and each dictionary has a key of  let s say   type  which can have values of  type1    type2   etc  My goal is to filter out these dictionaries into a list of the same dictionaries but only the ones of a certain  type   I think i m just really struggling with list dictionary comprehensions    so an example list would look like   exampleSet      type   type1     type   type2     type   type2      type   type3      i have a list of key values  lets say for example    keyValList     type2   type3     where the expected resulting list would look like    expectedResult      type   type2     type   type2     type   type3      I know i could do this with a set of for loops  I know there has to be a simpler way though  i found a lot of different flavors of this question but none that really fit the bill and answered the question  I would post an attempt at the answer    but they weren t that impressive  probably best to leave it open ended  any assistance would be greatly appreciated

User · Accepted Answer

You can try a list comp   gt  gt  gt  exampleSet      type   type1     type   type2     type   type2      type   type3     gt  gt  gt  keyValList     type2   type3    gt  gt  gt  expectedResult    d for d in exampleSet if d  type   in keyValList   gt  gt  gt  expectedResult    type    type2      type    type2      type    type3      Another way is by using filter   gt  gt  gt  list filter lambda d  d  type   in keyValList  exampleSet      type    type2      type    type2      type    type3

User · Answer

Use filter  or if the number of dictionaries in exampleSet is too high  use ifilter of the itertools module  It would return an iterator  instead of filling up your system s memory with the entire list at once   from itertools import ifilter for elem in ifilter lambda x  x  type   in keyValList  exampleSet       print elem

[python] python filter list of dictionaries based on key value

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