Cast Value As Negative Float If There Is A "-" Sign At The End With Pandas

Within a dataframe I have a column called 'Val' where I have float values, but the negative values are represented by the '-' sign AT THE END! And therefore it is interpreted as ob

Solution 1:

You can use loc to correct only entries ending with -

mask = df.Val.str.endswith('-')
df.loc[mask, 'Val'] = '-' + df.loc[mask, 'Val'].str[:-1]

and then convert to numeric dtype

df['Val'] = pd.to_numeric(df.Val, errors='coerce')

Final result

50.01873     -0.2496100.04252.0Name:Val,dtype:float64

Solution 2:

You can do with str.strip, then using np.where with str.endswith

s1=df.x.str.strip('+|-').astype('float')
np.where(df.x.str.endswith('-'),s1*-1,s1)
array([  0. ,  -0.2, 100. ,   2. ])