CODEWITHSUNDEEP
pythondeep-copy
E. Aly
E. Aly

Reputation: 331

Unexpected behaviour after using "deepcopy"

When I run the following code, it doesn't modify the list generated using 'deepcopy', i.e. I get 'mt1' unchanged. If I applied the same code on 'mt', I get the desired result!

def subDic(f):
    w = random.randint(2, int(0.7*len(f)))
    s = random.randint(0, len(f)-w)
    idSub = {}
    for i in range(s, s+w):
        idSub[i] = f[i]
    return idSub


ft = [(2,3), (4,8), (1,0), (7,1)]
mt = copy.deepcopy(ft)
random.shuffle(mt)
mt1 = copy.deepcopy(mt)

ftDic = subDic(ft)
for e in mt1:
    if e in ftDic.values():
        mt1.remove(e)

Upvotes: 0

Views: 74

Answers (1)

KelvinS
KelvinS

Reputation: 3071

You shouldn't iterate over mt1 while removing its values.

Try something like this:

def subDic(f):
    w = random.randint(2, int(0.7*len(f)))
    s = random.randint(0, len(f)-w)
    idSub = {}
    for i in range(s, s+w):
        idSub[i] = f[i]
    return idSub


ft = [(2,3), (4,8), (1,0), (7,1)]
mt = copy.deepcopy(ft)
random.shuffle(mt)
mt1 = copy.deepcopy(mt)

ftDic = subDic(ft)
for e in ftDic.values():
    mt1.remove(e)

Upvotes: 2

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