Menu
isSubset() to check multiple keys exist in Dictionary The python isSubset() method returns true if all the elements of the set passed as argument present in another subset else return false.
No, each key in a dictionary should be unique. You can't have two keys with the same value. Attempting to use the same key again will just overwrite the previous value stored. If a key needs to store multiple values, then the value associated with the key should be a list or another dictionary.
Python dictionary multiple keys with same name In Python dictionary, if you want to display multiple keys with the same value then you have to use the concept of for loop and list comprehension method. Here we create a list and assign them a value 2 which means the keys will display the same name two times.
Well, you could do this:
>>> if all (k in foo for k in ("foo","bar")):
... print "They're there!"
...
They're there!
if {"foo", "bar"} <= myDict.keys(): ...
If you're still on Python 2, you can do
if {"foo", "bar"} <= myDict.viewkeys(): ...
If you're still on a really old Python <= 2.6, you can call set on the dict, but it'll iterate over the whole dict to build the set, and that's slow:
if set(("foo", "bar")) <= set(myDict): ...
Put in your own values for D and Q
>>> from timeit import Timer
>>> setup='''from random import randint as R;d=dict((str(R(0,1000000)),R(0,1000000)) for i in range(D));q=dict((str(R(0,1000000)),R(0,1000000)) for i in range(Q));print("looking for %s items in %s"%(len(q),len(d)))'''
>>> Timer('set(q) <= set(d)','D=1000000;Q=100;'+setup).timeit(1)
looking for 100 items in 632499
0.28672504425048828
#This one only works for Python3
>>> Timer('set(q) <= d.keys()','D=1000000;Q=100;'+setup).timeit(1)
looking for 100 items in 632084
2.5987625122070312e-05
>>> Timer('all(k in d for k in q)','D=1000000;Q=100;'+setup).timeit(1)
looking for 100 items in 632219
1.1920928955078125e-05
You don't have to wrap the left side in a set. You can just do this:
if {'foo', 'bar'} <= set(some_dict):
pass
This also performs better than the all(k in d...) solution.
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With