Python Exercise Example 38
Python 100 ExamplesQuestion:Find the sum of the elements on the main diagonal of a 3*3 matrix.
Program analysis:Use a double for loop to control the input of a two-dimensional array, then accumulate a[i][i] and output it.
Program source code:
Example
#!/usr/bin/python
# -*- coding: UTF-8 -*-
if __name__ == '__main__':
a = []
sum = 0.0
for i in range(3):
a.append([])
for j in range(3):
a[i].append(float(input("input num:\n")))
for i in range(3):
sum += a[i][i]
print (sum)
The output result of the above example is:
input num: 78 input num: 34 input num: 23 input num: 34 input num: 56 input num: 33 input num: 12 input num: 21 input num: 2 136.0Other Extensions