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  • Swap 2 Variables in Python

    In Python, it's concise, easy and faster to swap 2 variables compared in other Programming languages:

    Python:

    x, y = y, x

    Other programming languages:

    temp = x
    x = y
    y = temp

    Actually, we can also use the second method just like the other programming languages, but it's

    slower than the firt method. Why? Let's take a look at the following codes:

    >>> x = 1
    >>> y = 2
    >>> x
    1
    >>> y
    2
    >>> id(x)
    160123056
    >>> id(y)
    160123044
    >>> x, y = y, x
    >>> x
    2
    >>> y
    1
    >>> id(x)
    160123044
    >>> id(y)
    160123056
    >>> x = 1
    >>> y = 2
    >>> x
    1
    >>> y
    2
    >>> id(x)
    160123056
    >>> id(y)
    160123044
    >>> temp = x
    >>> id(temp)
    160123056
    >>> x = y
    >>> y = temp
    >>> id(x)
    160123044
    >>> id(y)
    160123056
    >>> x
    2
    >>> y
    1

    As we can see the codes above, the second method involves a new variables 'temp' while the first method not,

    so the second method is slower than the first method.

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  • 原文地址:https://www.cnblogs.com/lxw0109/p/swap_variables.html
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