I have a DataFrame that looks like this:

What I would like to do is to compare the values in all four columns (A, B, C, and D) for every row and count the number of times in which D has the smaller value than A, B, or C for each row and add it into the ‘Count’ column. So for instance, ‘Count’ should be 1 for the second row, the third row, and 2 for the last row.

Thank you in advance!

### >Solution :

In the future, please do not post data as an image.

Use a lambda function and compare across all columns, then sum across the columns.

```
data = {'A': [1,47,4316,8511],
'B': [4,1,3,4],
'C': [2,7,9,1],
'D': [32,17,1,0]
}
df = pd.DataFrame(data)
df['Count'] = df.apply(lambda x: x['D'] < x, axis=1).sum(axis=1)
```

Output:

```
A B C D Count
0 1 4 2 32 0
1 47 1 7 17 1
2 4316 3 9 1 3
3 8511 4 1 0 3
```