在二维数组中查找点

Question

I've started coding recently and my preferred language is python. I've come across a problem I'm having trouble with.

The problem is finding the index in a 2d array where the number is either larger than the numbers to the left and right and smaller than the numbers above and below or vice versa.

I know a 2d array can be defined as list = [[1, 2], [3, 4], [5, 6]] but as for working out the algorithm to sort the problem is at the present time beyond me. Could someone please offer a solution?

Answer 1

min(enumerate(list[0]),key=lambda x:x[1]) will find the (index,value) pair with the smallest value from list[0] ((0,1) in this example). max(enumerate(list[0]),key=lambda x:x[1]) will find the largest.

Note (since you said you're new) this is the same as:

def first_index(L):
    return l[1]
min(enumerate(list[0]),key=first_index)

new_list=[L[0] for L in list] will make a list containing the 0th element from each list ([1,3,5] in this example). You'll probably want to do this for each column using for index in range(len(list[0]):

Note (since you're new) this is the same as:

new_list=list()
for L in list:
    new_list.append(L[0])