Why subtract a value from itself (x - x) in Python?

Posted by endolith on Stack Overflow See other posts from Stack Overflow or by endolith
Published on 2010-05-20T15:06:45Z Indexed on 2010/05/20 15:10 UTC
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python

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type-conversion

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type

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numpy

In NumPy functions, there are often initial lines that do checking of variable types, forcing them to be certain types, etc. Can someone explain the point of these lines? What does subtracting a value from itself do?

t,w = asarray(t), asarray(duty)
w = asarray(w + (t-t))
t = asarray(t + (w-w))

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