CODEWITHSUNDEEP
pythonpython-3.xpandas
Hariom Singh
Hariom Singh

Reputation: 3632

Pandas convert column from str to float

For the below dataframe I am using the code 

df['%'] = ((df['Code Lines'] / df['Code Lines'].sum()) * 100).round(2).astype(str) + '%'

output

Language    # of Files  Blank Lines Comment Lines   Code Lines  % 
C++              15          66           35            354    6.13%
C/C++ Header      1           3            7              4    0.07%
Markdown          6           73           0            142    2.46%
Python           110         1998       2086           4982    86.27%
Tcl/Tk            1          14           18            273    4.73%
YAML              1           0            6             20    0.35%

I am trying to convert the str to float 

df['%'] = df['% of Total (Code Only)'].astype('float64')

Getting error

File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/pandas/core/dtypes/cast.py", line 730, in astype_nansafe return arr.astype(dtype, copy=True) ValueError: could not convert string to float: '0.35%'

is there a way to maintain the column % as float along with sign %

Upvotes: 3

Views: 10262

Answers (3)

Shrikanth N
Shrikanth N

Reputation: 652

You can remove the last character from string as shown below:

str[:-1] removes the last character

df['%'] = df['%'].str[:-1].astype('float64')

Or you can use replace() to replace % with a blank character.

df['%'] = df['%'].replace("%","").astype('float64')

Upvotes: 0

sacuL
sacuL

Reputation: 51335

Another way, using strip:

df['%'] = df['%'].str.strip('%').astype('float64')

0     6.13
1     0.07
2     2.46
3    86.27
4     4.73
5     0.35
Name: %, dtype: float64

Upvotes: 1

jezrael
jezrael

Reputation: 862661

Use str[:-1] for remove last value (%) by indexing with str:

df['%'] = df['%'].str[:-1].astype('float64')

But if possible better is:

df['%'] = ((df['Code Lines'] / df['Code Lines'].sum()) * 100).round(2)

print (df)
       Language  # of Files  Blank  Lines Comment  Lines Code Lines      %
0           C++          15     66             35               354   6.13
1  C/C++ Header           1      3              7                 4   0.07
2      Markdown           6     73              0               142   2.46
3        Python         110   1998           2086              4982  86.27
4        Tcl/Tk           1     14             18               273   4.73
5          YAML           1      0              6                20   0.35

Upvotes: 7

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