Python : Multiple inheritance problems












0















I'm a little confused about an inheritance problem in python.

I know the following example is "stupid" but I simplify my initial problem.

Imagine we have 3 classes



class testT(object):

    def check(self, str):

       return "t" in str



class testTE(testT):

    def check(self, str):

       return "e" in str



class testTES(testTE):

    def check(self, str):

       return "s" in str


And I would like an output like :



>>> print testTES().check("test")

>>> True    (Because string "test" contains "s","e" and "t" characters)

>>> print testTES().check("dog")

>>> False

>>> print testTES().check("dogs")

>>> False   (Contains a "s" but no "e" and no "t")

>>> print testTE().check("tuple")

>>> True    (Contains "e" and "t")


How can I implement this behavior ? I tried with 'super' but my method wasn't successfull.

Thanks for your help






python inheritance







share|improve this question


















  • 1





    Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

    – jdehesa
    Nov 27 '18 at 15:51


















0















I'm a little confused about an inheritance problem in python.

I know the following example is "stupid" but I simplify my initial problem.

Imagine we have 3 classes



class testT(object):

    def check(self, str):

       return "t" in str



class testTE(testT):

    def check(self, str):

       return "e" in str



class testTES(testTE):

    def check(self, str):

       return "s" in str


And I would like an output like :



>>> print testTES().check("test")

>>> True    (Because string "test" contains "s","e" and "t" characters)

>>> print testTES().check("dog")

>>> False

>>> print testTES().check("dogs")

>>> False   (Contains a "s" but no "e" and no "t")

>>> print testTE().check("tuple")

>>> True    (Contains "e" and "t")


How can I implement this behavior ? I tried with 'super' but my method wasn't successfull.

Thanks for your help






python inheritance







share|improve this question


















  • 1





    Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

    – jdehesa
    Nov 27 '18 at 15:51
















0












0








0








I'm a little confused about an inheritance problem in python.

I know the following example is "stupid" but I simplify my initial problem.

Imagine we have 3 classes



class testT(object):

    def check(self, str):

       return "t" in str



class testTE(testT):

    def check(self, str):

       return "e" in str



class testTES(testTE):

    def check(self, str):

       return "s" in str


And I would like an output like :



>>> print testTES().check("test")

>>> True    (Because string "test" contains "s","e" and "t" characters)

>>> print testTES().check("dog")

>>> False

>>> print testTES().check("dogs")

>>> False   (Contains a "s" but no "e" and no "t")

>>> print testTE().check("tuple")

>>> True    (Contains "e" and "t")


How can I implement this behavior ? I tried with 'super' but my method wasn't successfull.

Thanks for your help






python inheritance







share|improve this question














I'm a little confused about an inheritance problem in python.

I know the following example is "stupid" but I simplify my initial problem.

Imagine we have 3 classes



class testT(object):

    def check(self, str):

       return "t" in str



class testTE(testT):

    def check(self, str):

       return "e" in str



class testTES(testTE):

    def check(self, str):

       return "s" in str


And I would like an output like :



>>> print testTES().check("test")

>>> True    (Because string "test" contains "s","e" and "t" characters)

>>> print testTES().check("dog")

>>> False

>>> print testTES().check("dogs")

>>> False   (Contains a "s" but no "e" and no "t")

>>> print testTE().check("tuple")

>>> True    (Contains "e" and "t")


How can I implement this behavior ? I tried with 'super' but my method wasn't successfull.

Thanks for your help






python inheritance




python inheritance






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 27 '18 at 15:40









Renaud MichotteRenaud Michotte

748




748








  • 1





    Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

    – jdehesa
    Nov 27 '18 at 15:51
















  • 1





    Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

    – jdehesa
    Nov 27 '18 at 15:51










1




1





Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

– jdehesa
Nov 27 '18 at 15:51







Just as a comment, note that this is not what is known as multiple inheritance. Here every class has a single parent so it is single inheritance (even if the inheritance hierarchy has more than one level). Multiple inheritance occurs when a class has more than one parent at the same time, leading to issues like the "diamond problem" and confusing priority rules in the case two inherited methods have the same signature (or just the same name, in Python).

– jdehesa
Nov 27 '18 at 15:51














1 Answer
1






active

oldest

votes


















4














You just need to combine the check calls in the subclasses with the output of super(...).check():



class testT(object):

    def check(self, str):

        return "t" in str



class testTE(testT):

    def check(self, str):

        return super(testTE, self).check(str) and "e" in str



class testTES(testTE):

    def check(self, str):

        return super(testTES, self).check(str) and "s" in str



print(testTES().check("test"))

# True

print(testTES().check("dog"))

# False

print(testTES().check("dogs"))

# False

print(testTE().check("tuple"))

# True





share|improve this answer





















  • 1





    Note OP appears to be using Python 2, so super and print would be slightly different in that case.

    – jdehesa
    Nov 27 '18 at 15:47











  • @jdehesa I fixed the calls to super, in this case print(...) works

    – DeepSpace
    Nov 27 '18 at 15:48











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1 Answer
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oldest

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1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









4














You just need to combine the check calls in the subclasses with the output of super(...).check():



class testT(object):

    def check(self, str):

        return "t" in str



class testTE(testT):

    def check(self, str):

        return super(testTE, self).check(str) and "e" in str



class testTES(testTE):

    def check(self, str):

        return super(testTES, self).check(str) and "s" in str



print(testTES().check("test"))

# True

print(testTES().check("dog"))

# False

print(testTES().check("dogs"))

# False

print(testTE().check("tuple"))

# True





share|improve this answer





















  • 1





    Note OP appears to be using Python 2, so super and print would be slightly different in that case.

    – jdehesa
    Nov 27 '18 at 15:47











  • @jdehesa I fixed the calls to super, in this case print(...) works

    – DeepSpace
    Nov 27 '18 at 15:48
















4














You just need to combine the check calls in the subclasses with the output of super(...).check():



class testT(object):

    def check(self, str):

        return "t" in str



class testTE(testT):

    def check(self, str):

        return super(testTE, self).check(str) and "e" in str



class testTES(testTE):

    def check(self, str):

        return super(testTES, self).check(str) and "s" in str



print(testTES().check("test"))

# True

print(testTES().check("dog"))

# False

print(testTES().check("dogs"))

# False

print(testTE().check("tuple"))

# True





share|improve this answer





















  • 1





    Note OP appears to be using Python 2, so super and print would be slightly different in that case.

    – jdehesa
    Nov 27 '18 at 15:47











  • @jdehesa I fixed the calls to super, in this case print(...) works

    – DeepSpace
    Nov 27 '18 at 15:48














4












4








4







You just need to combine the check calls in the subclasses with the output of super(...).check():



class testT(object):

    def check(self, str):

        return "t" in str



class testTE(testT):

    def check(self, str):

        return super(testTE, self).check(str) and "e" in str



class testTES(testTE):

    def check(self, str):

        return super(testTES, self).check(str) and "s" in str



print(testTES().check("test"))

# True

print(testTES().check("dog"))

# False

print(testTES().check("dogs"))

# False

print(testTE().check("tuple"))

# True





share|improve this answer















You just need to combine the check calls in the subclasses with the output of super(...).check():



class testT(object):

    def check(self, str):

        return "t" in str



class testTE(testT):

    def check(self, str):

        return super(testTE, self).check(str) and "e" in str



class testTES(testTE):

    def check(self, str):

        return super(testTES, self).check(str) and "s" in str



print(testTES().check("test"))

# True

print(testTES().check("dog"))

# False

print(testTES().check("dogs"))

# False

print(testTE().check("tuple"))

# True






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 27 '18 at 15:47

























answered Nov 27 '18 at 15:46









DeepSpaceDeepSpace

39.1k44473




39.1k44473








  • 1





    Note OP appears to be using Python 2, so super and print would be slightly different in that case.

    – jdehesa
    Nov 27 '18 at 15:47











  • @jdehesa I fixed the calls to super, in this case print(...) works

    – DeepSpace
    Nov 27 '18 at 15:48














  • 1





    Note OP appears to be using Python 2, so super and print would be slightly different in that case.

    – jdehesa
    Nov 27 '18 at 15:47











  • @jdehesa I fixed the calls to super, in this case print(...) works

    – DeepSpace
    Nov 27 '18 at 15:48








1




1





Note OP appears to be using Python 2, so super and print would be slightly different in that case.

– jdehesa
Nov 27 '18 at 15:47





Note OP appears to be using Python 2, so super and print would be slightly different in that case.

– jdehesa
Nov 27 '18 at 15:47













@jdehesa I fixed the calls to super, in this case print(...) works

– DeepSpace
Nov 27 '18 at 15:48





@jdehesa I fixed the calls to super, in this case print(...) works

– DeepSpace
Nov 27 '18 at 15:48




















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