将数组转换为0和1

Question

Suppose I have an array A = [13, 15, 17] . I want to create a new array B such that all entries apart from its 13th, 15th and 17th entries are 0 , and each of these three are 1 's. How can I do this?

Answer 1

Use a list comprehension:

B = [int(i+1 in A) for i in range(max(A))]

For each number in the range from 0 to the highest number in A , we take int(i+1 in A) . i+1 in A will be a boolean value. If that number is in A , the result will be True . Otherwise it will be False . Since bool inherits from int , we can easily convert it to a normal integer with int() .