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Python array practice problem analysis, for this problem, this article details the corresponding analysis and solution, hoping to help more small partners who want to solve this problem find a simpler and easier way.

Python arrays have a lot of knowledge that requires detailed study. Python arrays do not have array data structures, but lists look like arrays, such as:

a=[0,1,2] In this case a[0]=0, a[1]=1, a[[2]=2, but this leads to the question of what to do if the array a wants to be defined as 0 to 999, which can be achieved by a = range(0, 1000). or omitted as a = range(1000). If you want to define a with a length of 1000 and all initial values are 0, then a = [0 for x in range(0, 1000)] Here is the definition of a two-dimensional array:

A=[[1,1],[1,1]] is defined directly, where a 2*2 two-dimensional array is defined, and the initial value is 0.

Indirectly define a=[[0 for x in range(10)] for y in range(10)], where 10*10 is defined as a two-dimensional array initially 0.

Later, I found a simpler way to use two-dimensional arrays online:

b = [[0]*10]*10, defines a two-dimensional array of 10*10 initially 0.

Compare with a=[0 for x in range(10)] for y in range(10)]: print a==b results in True.

However, after replacing a with the definition method of b, the previous program that can run normally is also wrong. After careful analysis, the difference is obtained:

A[0][0]=1, only a[0][0] is 1, and all others are 0.

[1][2][3][4][5][6][7][8][9][9][9][10][11][12][13][14][15][16][17][18][19][19][19]

The result is that the 10 small one-dimensional data in the large array are all the same reference, that is, pointing to the same address.

Therefore b = [[0]*10]*10 does not correspond to a two-dimensional array in our conventional sense.

At the same time, after testing: the definition of c=[0]*10 has the same effect as c=[0 for x in range(10)], without the same problem of reference above, it is estimated that the definition of Python array c is value type multiplication, while the previous b is multiplied by type, because the one-dimensional array is a reference (borrowing the value type and reference type in C#, I wonder if it is appropriate).

About Python array practice problem analysis questions to share here, I hope the above content can be of some help to everyone, if you still have a lot of doubts not solved, you can pay attention to the industry information channel to learn more related knowledge.

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