I need print the coordinates of matrix whose corresponding row and columns are only zeros

Example:

```
3 3
1 0 0
0 0 0
1 0 0
```

in above example at coordinate (1,1) rows and cols are zero(0) like that I need to print all coronates having row and col as zero.(like need to check in **plus shape**)

My code:

```
r,c=map(int,input().split())
l=[list(map(int,input().split())) for i in range(r)]
for i in range(len(l)):
for j in range(0,len(l[i])):
if sum(l[i])==0 and sum(l[j])==0:
print(i,j)
```

my code is working for above mentioned input but for bellow mention input not working why??

input:

```
6 13
1 0 1 0 1 0 1 0 1 0 1 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0
0 1 0 1 0 1 0 1 0 1 0 1 0
```

output needed:

```
1 13
2 13
3 13
4 13
```

my output:

```
1 1
1 2
1 3
1 4
Traceback (most recent call last):
File "main.py", line 5, in <module>
if sum(l[i])==0 and sum(l[j])==0:
IndexError: list index out of range
```

What mistake i made? Please help me!!

### >Solution :

Based on how you are iterating over the table, `l[i]`

will indeed give you the ith row of l, but `l[j]`

will give you the jth row of table l, whereas you are actually wanting the jth column of l.

The index error occurs b/c you have more columns than rows, and so you eventually attempt to access the 7th *row* (rather than column) which indeed does not exist

Not the most efficient way to do this but to get the jth column you could iterate over each l[x][j] for each row x: `sum(l[x][j] for x in range(len(l))])`

To wit:

```
r,c=map(int,input().split())
l=[list(map(int,input().split())) for i in range(r)]
for i in range(len(l)):
for j in range(0,len(l[i])):
if sum(l[i])==0 and sum(l[x][j] for x in range(len(l)))==0:
print(i,j)
# Outputs:
1 12
2 12
3 12
4 12
```

On the test case above