How do I get a list values and columns using python?

Question

Apologies for the noobish question but....

I have a dataframe (in python using pandas, with headers) which looks like this:

   Pink     Blue    Yellow   Green  
 --------- ------- -------- ------- 
  Jackson   Bryan   Bruce    Benji  
  James     Jonah   Jenny    Kevin  
  Tyson     Jenna   Mike     none   
  Kendall   Amy     Alison   none   
  Ben       none    none     none

How do I get a list of teams and names to look like below?

  Pink    Jackson  
  Pink    James    
  Blue    Bryan    
  ...              
  Green   Kevin

So you want all pairs of column name + value?

L3n95
– L3n95

2020-05-14 14:56:50 +00:00
Commented May 14, 2020 at 14:56 — L3n95
– L3n95, Commented May 14, 2020 at 14:56
Does this answer your question? How to pivot a dataframe

Dave
– Dave

2020-05-14 15:01:36 +00:00
Commented May 14, 2020 at 15:01 — Dave
– Dave, Commented May 14, 2020 at 15:01

L3n95 · Accepted Answer · 2020-05-14 15:05:57Z

1

If I got it right, you want to have all pairs of column name + value. pd.melt can do that for you:

 df = pd.DataFrame({"Pink": ["Jackson", "James"], "Blue": ["Bryan", None]})
 pd.melt(df)

Result:

  variable    value
0     Pink  Jackson
1     Pink    James
2     Blue    Bryan
3     Blue     None

And if you only want a 2-dimensional numpy array you can do:

pd.melt(df).values

Result:

array([['Pink', 'Jackson'],
       ['Pink', 'James'],
       ['Blue', 'Bryan'],
       ['Blue', None]], dtype=object)

And as matman9 pointed out just add a .tolist() after the .values to get a python list.

edited May 14, 2020 at 15:05

answered May 14, 2020 at 15:01

L3n95

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2 Comments

Vaidøtas I. Over a year ago

Beat me to it :D

matman9 Over a year ago

to get the list you can add .tolist() after values

Błotosmętek · Accepted Answer · 2020-05-14 15:51:23Z

0

In addition to the earlier answer I'd suggest filtering out the None's:

for t in filter(lambda x: x[1], pd.melt(df).values.tolist()):
    print('{:8} {}'.format(*t))

answered May 14, 2020 at 15:51

Błotosmętek

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