CODEWITHSUNDEEP
pythonpython-2.7python-3.xreplacefilter
Tee Pee
Tee Pee

Reputation: 73

AttributeError: 'filter' object has no attribute 'replace' in Python 3

I have some problems with python 3.x. In python 2.x. I could use replace attr in filter obj, but now I cannot use this. Here is a section of my code:

def uniq(seq):
    seen = {}
    return [seen.setdefault(x, x) for x in seq if x not in seen]

def partition(seq, n):
    return [seq[i : i + n] for i in xrange(0, len(seq), n)]

def PlayFairCipher(key, from_ = 'J', to = None):
    if to is None:
        to = 'I' if from_ == 'J' else ''

    def canonicalize(s):
        return list(filter(str.isupper, s.upper()).replace(from_, to))

    m = partition(uniq(canonicalize(key + ascii_uppercase)), 5)

    enc = {}

    for row in m:
        for i, j in product(xrange(5), repeat=2):
            if i != j:
                enc[row[i] + row[j]] = row[(i + 1) % 5] + row[(j + 1) % 5]

    for c in zip(*m):
        for i, j in product(xrange(5), repeat=2):
            if i != j:
                enc[c[i] + c[j]] = c[(i + 1) % 5] + c[(j + 1) % 5]

    for i1, j1, i2, j2 in product(xrange(5), repeat=4):
        if i1 != i2 and j1 != j2:
            enc[m[i1][j1] + m[i2][j2]] = m[i1][j2] + m[i2][j1]

    def sub_enc(txt):
        lst = findall(r"(.)(?:(?!\1)(.))?", canonicalize(txt))
        return ''.join(enc[a + (b if b else 'X')] for a, b in lst)

    return sub_enc

But when this compiled, I receive this:

AttributeError: 'filter' object has no attribute 'replace'

How can I fix it?

Upvotes: 2

Views: 2906

Answers (2)

Jean-François Fabre
Jean-François Fabre

Reputation: 140256

in python 2, filter returns a string if a string is passed as input.

filter(...) filter(function or None, sequence) -> list, tuple, or string

Return those items of sequence for which function(item) is true. If function is None, return the items that are true. If sequence is a >tuple or string, return the same type, else return a list.

To simulate this behaviour in python 3 just do

"".join(filter(str.isupper, s.upper()))

to convert the iterable to string, then you can perform the replace

Upvotes: 3

Patrick Haugh
Patrick Haugh

Reputation: 61032

I think you can use a list comprehension:

[c.replace(from_, to) for c in s.upper() if c.isupper()]

Is this what you want? There's a lot of code there so I might be missing something

Upvotes: 1

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