Notes when initializing arrays that store weights and biases

[python] [array]

Array initialization

＜ Initialize an empty array＞

array_a = []

＜Initialize after entering a number＞

array_b = [1, 2, 3, 4]

＊You can also enter strings and variables

Initialize after filling the specified number with 0

For example, if you want to initialize a 1 × 10 array

array1 = [0]*10

What about 10x10? ?

array2 = [[0]*10]*10

OK, OK, array initialization succeeded.
But please wait a moment.
Change the value in the 5th row and the 4th column to 48.

！！！！！！！！！

No, this must be something wrong …
Try changing the value in row 9 and column 9 to 12.

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

All the columns have been updated …

Use ”for i in range”

If you want to update only the specified element, initialize the array as follows.

array3 = [[0 for i in range(10)]for i in range(10)]

Change the value in the 5th row and the 4th column to 48.

Try changing the value in 9th row and 9th column to 12.

Congratulations‼
Updated successfully.

Conclusion

The [[0] * 10] * 10 method defines 10 identical arrays, so changing the value of an element changes the other elements.
The [[0 for i in range (10)] for i in range (10)] method creates multiple lists. Therefore, the value of only the specified element is changed.