# Input numbers in nested list and find the sum of each row, column, right and left diagonal in Python

###### Lists - Question 12

In this question, we will see how to input numbers in a 3X3 integer matrix (nested list) and find the sum of each row, each column, right diagonal and left diagonal separately in Python programming. To know more about lists click on the lists lesson.

**Q12)** Write a program in Python to input numbers in a 3X3 integer matrix (nested list) and find the sum of each row, each column, right diagonal and left diagonal separately. Right Diagonal = \ and Left Diagonal = /.

#### Program

```
a=[[],[],[]]
r=0;c=0;rs=0;cs=0;rd=0;ld=0
print('Enter 9 numbers')
for r in range(3):
for c in range(3):
a[r].append(int(input()))
for r in range(3):
rs=0
cs=0
rd=rd+a[r][r]
ld=ld+a[r][2-r]
for c in range(3):
print(a[r][c],end=' ')
rs=rs+a[r][c]; # row sum
cs=cs+a[c][r]; # column sum
print(' Row Sum = %d Column Sum = %d' %(rs,cs))
print('Right Diagonal Sum =',rd)
print('Left Diagonal Sum =',ld)
```

#### Output

Enter 9 numbers 18 12 72 10 15 45 38 5 64 18 12 72 Row Sum = 102 Column Sum = 66 10 15 45 Row Sum = 70 Column Sum = 32 38 5 64 Row Sum = 107 Column Sum = 181 Right Diagonal Sum = 97 Left Diagonal Sum = 125