dataframe duplicated rows code example

Example 1: print duplicates elements in column pandas

mask = df.columnname.duplicated(keep=False)
print (df[mask])

Example 2: how to duplicate a row in python

import pandas as pd

In [603]: df = pd.DataFrame({'col1':list("abc"),'col2':range(3)},index = range(3))

In [604]: df
Out[604]: 
  col1  col2
0    a     0
1    b     1
2    c     2

In [605]: pd.concat([df]*3, ignore_index=True) # Ignores the index
Out[605]: 
  col1  col2
0    a     0
1    b     1
2    c     2
3    a     0
4    b     1
5    c     2
6    a     0
7    b     1
8    c     2

In [606]: pd.concat([df]*3)
Out[606]: 
  col1  col2
0    a     0
1    b     1
2    c     2
0    a     0
1    b     1
2    c     2
0    a     0
1    b     1
2    c     2