operators - What does ,= mean in python? -

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i wonder ,= or , = means in python?

example matplotlib:

plot1, = ax01.plot(t,yp1,'b-')

it's form of tuple unpacking. parentheses:

(plot1,) = ax01.plot(t,yp1,'b-')

ax01.plot() returns tuple containing 1 element, , element assigned plot1. without comma (and possibly parentheses), plot1 have been assigned whole tuple. observe difference between a , b in following example:

>>> def foo(): ...     return (1,) ...  >>> (a,) = foo() >>> b = foo() >>> 1 >>> b (1,)

you can omit parentheses both in (a,) , (1,), left them sake of clarity.


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