Searching a list of objects in Python

Question

Let\'s assume I\'m creating a simple class to work similar to a C-style struct, to just hold data elements. I\'m trying to figure out how to search a list of objects for ob

Answer 1

filter(lambda x: x.n == 5, myList)

Answer 2

You can use in to look for an item in a collection, and a list comprehension to extract the field you are interested in. This (works for lists, sets, tuples, and anything that defines __contains__ or __getitem__).

if 5 in [data.n for data in myList]:
    print "Found it"

See also:

• Contains Method
• In operation

Answer 3

[x for x in myList if x.n == 30]               # list of all matches
[x.n_squared for x in myList if x.n == 30]     # property of matches
any(x.n == 30 for x in myList)                 # if there is any matches
[i for i,x in enumerate(myList) if x.n == 30]  # indices of all matches

def first(iterable, default=None):
  for item in iterable:
    return item
  return default

first(x for x in myList if x.n == 30)          # the first match, if any