Zamijena duplih vrijednosti u koloni sa nulom (praznim poljem).

   a      c1   c2
0  Male   3    10
1              30
2  Male   1    20
3  Female 2    15
4             100

In [131]:
df.loc[df['c1'].duplicated(), 'c1'] = ''
df

Out[131]:
  c1   c2
0  3   10
1      30
2  1   20
3  2   15
4     100

df.to_csv('pandasfile.csv', float_format='%.3f', index=False) 

Source: Stackoverflow 
 

Python is open source. It’s great, but has the inherent problem of open source: many packages do (or try to do) the same thing. If you’re new to Python, it’s hard to know the best package for a specific task. You need someone who has experience to tell you. And I tell you today: there’s one package you absolutely need to learn for data science, and it’s called pandas.

And what’s really interesting with pandas, is that many other packages are hidden in it. Pandas is a core package plus features from a variety of other packages. And that’s great, because you can work only using pandas.

Pandas is like Excel in Python: it uses tables (namely DataFrame) and operates transformations on the data. But it can do a lot more.

Ostatak teksta na https://towardsdatascience.com/be-a-more-efficient-data-scientist-today-master-pandas-with-this-guide-ea362d27386