CODEWITHSUNDEEP
pythonpython-3.xpandasdataframe
codeninja
codeninja

Reputation: 379

Repeat an element in a dataframe

Sorry for the basic question but I can't seem to figure this out. I have the following dataframe:

df1
      a              
1     7           
2     26             
3     32            
4     41             
...   
37    7
38    9

How would I go about repeating the value at the 37th index, twice such that the following is produced

df1
      a              
1     7           
2     26             
3     32            
4     41             
...   
37    7
38    7
39    9

I've tried to use loc to no avail:

 newp = df1[name].loc[np.repeat(df1.index[-2:].values, 1)] #get the 37th index value to repeat
 listofwty[0].loc[36] = newp
 listofwty[0].index = listofwty.index+1

Upvotes: 1

Views: 66

Answers (2)

unutbu
unutbu

Reputation: 879191

You could use df.index.insert to insert another entry of 37, and then use df.reindex to duplicate the row:

import pandas as pd
df = pd.DataFrame({'a': [7, 26, 32, 41, 7, 9]}, index=[1, 2, 3, 4, 37, 38])
index = df.index
df = df.reindex(index.insert(index.get_loc(37), 37))
print(df)

yields

     a
1    7
2   26
3   32
4   41
37   7
37   7
38   9

Note this create a DataFrame with a non-unique index. To make the index labels unique, call df = df.reset_index(drop=True) (as Scott Boston showed in his answer).

Upvotes: 3

Scott Boston
Scott Boston

Reputation: 153460

You could do it this way, using pd.concat, then sort_index:

pd.concat([df,df.loc[[37]]]).sort_index().reset_index(drop=True)

Output:

     a
1    7
2   26
3   32
4   41
...
37   7
38   7
39   9

Upvotes: 2

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