how to sort dataframe based on particular (string)columns using python pandas?

Question

My Pandas data frame contains the following data:

product,values
 a1,     10
 a5,     20
 a10,    15
 a2,     45
 a3,     12
 a6,     67

I have to sort this data frame based on the product column. Thus, I would like to get the following output:

product,values
 a10,     15
 a6,      67
 a5,      20
 a3,      12
 a2,      45
 a1,      10

Unfortunately, I'm facing the following error:

ErrorDuringImport(path, sys.exc_info())

ErrorDuringImport: problem in views - type 'exceptions.Indentation

jezrael · Accepted Answer · 2019-07-11T12:16:13.297

17

You can first extract digits and cast to int by astype. Then sort_values of column sort and last drop this column:

df['sort'] = df['product'].str.extract('(\d+)', expand=False).astype(int)
df.sort_values('sort',inplace=True, ascending=False)
df = df.drop('sort', axis=1)
print (df)
  product  values
2     a10      15
5      a6      67
1      a5      20
4      a3      12
3      a2      45
0      a1      10

It is necessary, because if use only sort_values:

df.sort_values('product',inplace=True, ascending=False)
print (df)
  product  values
5      a6      67
1      a5      20
4      a3      12
3      a2      45
2     a10      15
0      a1      10

Another idea is use natsort library:

from natsort import index_natsorted, order_by_index

df = df.reindex(index=order_by_index(df.index, index_natsorted(df['product'], reverse=True)))
print (df)
  product  values
2     a10      15
5      a6      67
1      a5      20
4      a3      12
3      a2      45
0      a1      10

edited Jul 11 '19 at 12:16

answered Jun 08 '16 at 05:04

jezrael

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i m using python 2.7 version – Sai Rajesh Jun 08 '16 at 05:18
I think copy text of error, under tags in question give `edit` and paste text under text of question. Thanks. – jezrael Jun 08 '16 at 05:32
k now i will add that – Sai Rajesh Jun 08 '16 at 05:36
It looks like your `pandas` is broken - see [link](http://stackoverflow.com/q/14422976/2901002). – jezrael Jun 08 '16 at 05:51
what i have do now? – Sai Rajesh Jun 08 '16 at 05:54
Do you use anaconda? – jezrael Jun 08 '16 at 05:55
and python 2.7 version – Sai Rajesh Jun 08 '16 at 05:59
give me one solution – Sai Rajesh Jun 08 '16 at 06:00
maybe help try update pandas - if use `windows` - in `command line` use `conda update pandas` – jezrael Jun 08 '16 at 06:01
i m not able to do that..because that anoconda inbuilt in our product – Sai Rajesh Jun 08 '16 at 06:02
phoooo, so it is bigger problem. One idea - maybe if use lower version of pandas, try remove `, expand=False` from first row of code. What is version of pandas? `print pd.versions()` – jezrael Jun 08 '16 at 06:05
hm k...i will try that – Sai Rajesh Jun 08 '16 at 06:33
Super Ia am glad it working. Thank you for accepting. You can upvote too. – jezrael Jun 08 '16 at 06:47
how to add d in all rows? – Sai Rajesh Jun 08 '16 at 06:52
i mean my column contains 1,2,3,4,5 but i have to change d1,d2,d3,d4,d5 – Sai Rajesh Jun 08 '16 at 06:53
use list comprehension - `df.columns = ['d' + str(col) for col in df.columns]` – jezrael Jun 08 '16 at 06:59

how to sort dataframe based on particular (string)columns using python pandas?

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