IDL> array=[[11,22,33],[44,55,66],[77,88,99],[33,33,33]]
IDL> print, array
11 22 33
44 55 66
77 88 99
33 33 33
IDL> index = where(array eq 33)
IDL> result = ARRAY_INDICES(array, index)
IDL> print,result
2 0
0 3
1 3
2 3
result为一个二维数组，第一个列为array的列索引，第二列为array的行索引
array[2,0] = 33
array[0,3] = 33
array[1,3] = 33
array[2,3] = 33