如何在2D数组中查找值的地址

Question

I found a max_value (grayscale 2D array [50,200]) with

max = numpy.amax(matrice)

so it gives me a value. Now I want to know were I can find this value. I tried this code:

for x in range (1,50):  
for y in range (1,200):
if matrice[x,y]==max:
print ("[%s,%s]",x,y)

but it gives me an error message:

"for y in range (1,200): IndentationError: expected an indented block"

Can someone tell me what is the error or how I can find the address of this pixel?

Answer 1

The error is because you did not indent the line after the colon, so the syntax should look something like this:

for x in range (1,50):  
    for y in range (1,200):
        if matrice[x,y]==max:
            print ("[%s,%s]",x,y)

Try looking up the rules for indentation in Python, if you are in doubt about when you should use indentation.

Answer 2

You have to give tab indentation for each block

for x in range (1,50):  
    for y in range (1,200):
        if matrice[x,y]==max:
            print ("[%s,%s]",x,y)

Answer 3

As an alternative, you can vectorise your logic.

A = np.random.randint(0, 10, (5, 5))

print(A)

# [[4 9 3 0 8]
#  [5 0 3 9 0]
#  [2 2 4 1 5]
#  [3 5 9 0 0]
#  [9 5 7 9 5]]

res = np.argwhere(A==np.amax(A))

print(res)

# [[0 1]
#  [1 3]
#  [3 2]
#  [4 0]
#  [4 3]]