Python Initializes a multidimensional array of code
Source: Internet
Author: User
The best way to initialize a 5 x 3 array of 0 per item in Python is:
multilist = [[0 for Col inch Range ( 5 )] for Row inch Range ( 3 )]
We know that in order to initialize a one-dimensional array, we can do this:
alist = [0] * 5
Yes, if we initialize a two-dimensional array, can we do this:
Multi = [[0] * 5 ] * 3
In fact, this is wrong, because [0] * 5 is a one-dimensional array of objects, * 3 words just copy the object's Reference 3 times, for example, I modified multi[0][0]:
Multi = [[0] * 5 ] * 3
Multi[0][0] = ' Love China '
Print MultiThe result of the output will be:
[' Love China ', 0, 0, 0, 0], [' Love China ', 0, 0, 0, 0], [' Love China ', 0, 0, 0, 0]
We have modified multi[0][0], but we have changed our multi[1][0],multi[2][0. This is not the result we want.
If we write like this:
multilist = [[0] * 5 for Row inch Range ( 3 )]
Multilist[0][0] = ' Love China '
Print multilistWe look at the output:
[' Love China ', 0, 0, 0, 0], [0, 0, 0, 0, 0], [0, 0, 0, 0, 0]]
Yes, no problem. However, it is recommended to use the first method above, since the use of the * method is more likely to cause confusion than the bug, that is:
multilist = [[0 for Col inch Range ( 5 )] for Row inch Range ( 3 )]
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