import sys
import time

print("dict")
start = time.time()
d = dict((x, str(x)) for x in range(1000000))
print("Creation took", time.time() - start, "seconds")
start = time.time()
l = list(d)
for x in l:
    if x % 10 == 0:
        del d[x]
print("Deleting every tenth key took", time.time() - start, "seconds")
print("Memory used", sys.getsizeof(d) + sys.getsizeof(l))

print("OrderedDict")
from collections import OrderedDict
start = time.time()
o = OrderedDict((x, str(x)) for x in range(1000000))
print("Creation took", time.time() - start, "seconds")
start = time.time()
for x in o:
    if x % 10 == 0:
        del o[x]
print("Deleting every tenth key took", time.time() - start, "seconds")
print("Memory used", sys.getsizeof(o))



------------

Output:

dict
Creation took 0.6176350116729736 seconds
Deleting every tenth key took 0.24308395385742188 seconds
Memory used 29666016
OrderedDict
Creation took 4.645971059799194 seconds
Deleting every tenth key took 0.5459740161895752 seconds
Memory used 118732144