CODEWITHSUNDEEP
pythonpython-3.x
devolskii
devolskii

Reputation: 59

Expanding a List Comprehension

I have written this line as a single line for loop:

p.x, p.y, p.z = [float(s) for s in input('Input X, Y, Z: ').split()]

It works fine. But for my own understanding, I tried to expand it as this:

p.x, p.y, p.z = input('Input X, Y, Z: ').split()
float(p.x)
float(p.y)
float(p.z)

But it throws error (TypeError: unsupported operand type(s) for -: 'str' and 'str') whenever I try to do operations on them.

Can someone explain to me what I've done wrong and correct it?

Thanks a lot!

Upvotes: 0

Views: 127

Answers (1)

Mark
Mark

Reputation: 92471

As others have said, float() doesn't change the values of its input, it returns new values. A quick fix is to map() the float function onto the split input.

class P:
    pass

p = P()

p.x, p.y, p.z = map(float, input('Input X, Y, Z: ').split())

print(p.__dict__)
# Input X, Y, Z: 5.6 3.2 6.7
# {'x': 5.6, 'y': 3.2, 'z': 6.7}

You'll probably want to catch exceptions for bad input too.

Upvotes: 2

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