How to lower all the elements in a pandas dataframe?

Question

Just a quick question guys, I have a pandas dataframe: ``` In [11]: df = pd.DataFrame([['A', 'B'], ['C', E], ['D', 'C']],columns=['X', 'Y', 'Z']) In [12]: df Out[12]: X Y Z 0 A B D 1 C E C ``` How can I convert to lower all the elements of `df`: ``` Out[12]: X Y Z 0 a b d 1 c e c ``` I look over the documentation and I tried the following: ``` df = [[col.lower() for col in [df["X"],df["Y"], df["Z"]]]] df ``` Nevertheless, it doesnt work. How to lower all the elements inside a pandas dataframe?.

Accepted Answer

Either

```
df.applymap(str.lower)
Out: 
   X  Y  Z
0  a  b  d
1  c  e  c
```

Or

```
df.apply(lambda col: col.str.lower())
Out: 
   X  Y  Z
0  a  b  d
1  c  e  c
```

The first one is faster and it looks nicer but the second one can handle NaNs.

How to lower all the elements in a pandas dataframe?

Solution

Problem