CODEWITHSUNDEEP
python
user3072085
user3072085

Reputation: 1

'list' attribute has no attribute <function>

I am trying to create a class for Complex numbers that includes functions that operate on lists. I think my basic setup is okay because it works for functions that operate on single elements(like conjugate), but when I try to run functions like conjugateList, I get the error message "'list' object has no attribute 'conjugateList'. I am not sure how to address this problem. Thanks.

class Complex():
    def __init__(self, real= 0.0, imaginary= 0.0):
        self.real = real
        self.imaginary = imaginary

    def __str__(self):
        if self.imaginary < 0:
            printStr = str(self.real) + ' - ' + str(abs(self.imaginary))+ 'i'
        else:
            printStr = str(self.real) + ' + ' + str(self.imaginary)+ 'i'
        return printStr

    def conjugate(self):
        result = Complex()
        result.real = self.real
        result.imaginary = (self.imaginary * (-1))
        return result

    def conjugateList(lstC):
        newLst = []
        for elem in lstC:
        elem = elem.conjugate()
        newLst += elem
        return newLst

Upvotes: 0

Views: 736

Answers (2)

Jon Clements
Jon Clements

Reputation: 142226

Short of learning purposes for class design, for production you might want to use numpy:

>>> import numpy as np
>>> comps = np.array([complex(1, 1), complex(1, 2)])
>>> comps.dtype
dtype('complex128')
>>> comps.conjugate()
array([ 1.-1.j,  1.-2.j])

Upvotes: 0

Thomas Orozco
Thomas Orozco

Reputation: 55303

Because the conjugateList method isn't on your list, it's on the Complex object.

Note that this conjugateList method should actually be a staticmethod or — better yet — a function.

You would do:

class Complex():    
    # The rest of your stuff

    @staticmethod
    def conjugateList(lstC):
        newLst = []
        for elem in lstC:
            elem = elem.conjugate()
            newLst += elem
        return newLst

And then,

l1 = [Complex(1,1), Complex(1,2)]
l2 = Complex.conjugateList(l1)

Upvotes: 1

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