Line, = Plot(x,sin(x)) What Does Comma Stand For?

I'm trying to make an animated plot. Here is an example code: from pylab import * import time ion() tstart = time.time() # for profiling x = arange(0,2*pi,0.01)

Solution 1:

The comma is Python syntax that denotes either a single-element tuple. E.g.,

>>>tuple([1])
(1,)

In this case, it is used for argument unpacking: plot returns a single-element list, which is unpacked into line:

>>>x, y = [1, 2]>>>x
1
>>>y
2
>>>z, = [3]>>>z
3

An alternative, perhaps more readable way of doing this is to use list-like syntax:

>>>[z] = [4]>>>z
4

though the z, = is more common in Python code.

Solution 2:

case1:

a=1,
type(a)
tuple

case2:

a=1type(a)
int