```
df  = pd.DataFrame(columns=['w','x','y','z'])

```

I'm trying to insert a new index row by row, and add values to certain columns.
If I were adding one value to a specific column, I could do: `df.loc['a','x'] = 2`

However what if I'd like to add values to several columns in one go, like this:

```
{'x':2, 'z':3}

```

is there a way to do this in pandas?