Pandas: "ValueError: could not convert string to float: " (empty string)

Question

When trying to convert a Pandas Series to float, I get this error message. It refers to an empty string (" "), which is not a np.nan. Just an empty string.

I tried replacing " " by np.nan, but it doesn't do anything. I also tried replacing " " by "" but it also doesn't do anything.

import pandas as pd
import numpy as np

df = pd.DataFrame(np.array([[1, 2, 3], [4, " ", 6], [7, 8, 9]]), 
                  columns=['a', 'b', 'c'])

df.astype(float)

ValueError: could not convert string to float:

I want to replace these " " by NaN values, in a large dataframe.

What float value are you expecting for " " ?

user10417531
– user10417531

2019-05-16 14:53:29 +00:00
Commented May 16, 2019 at 14:53 — user10417531
– user10417531, Commented May 16, 2019 at 14:53
df.apply(pd.to_numeric, args=('coerce',))

VnC
– VnC

2019-05-16 14:59:09 +00:00
Commented May 16, 2019 at 14:59 — VnC
– VnC, Commented May 16, 2019 at 14:59

Asnim P Ansari · Accepted Answer · 2019-05-16 14:54:24Z

3

You can use df.replace() function to perform this operation

df.replace(r'^\s*$', np.nan, regex=True)

answered May 16, 2019 at 14:54

Asnim P Ansari

2,5553 gold badges30 silver badges50 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Pandas: "ValueError: could not convert string to float: " (empty string)

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related