Convert Numpy array to Pandas DataFrame column-wise (As Single Row)

Question

I have a numpy array looking like this:

a = np.array([35,2,160,56,120,80,1,1,0,0,1])

Then I'm trying to transform that array into pandas dataframe with logic "one column-one value" like this:

columns=['age','gender','height',
     'weight','ap_hi','ap_lo',
     'cholesterol','gluc','smoke',
     'alco','active']

values = a

df = pd.DataFrame(a,columns=columns)

This approach raises ValueError: Shape of passed values is (1, 11), indices imply (11, 11). What am I doing wrong and how to perform it in a right way?

Thanks!

baldassarreFe · Accepted Answer · 2017-07-26 14:00:17Z

24

You need numpy.reshape:

columns=['age','gender','height',
     'weight','ap_hi','ap_lo',
     'cholesterol','gluc','smoke',
     'alco','active']

a = np.array([35,2,160,56,120,80,1,1,0,0,1])

df = pd.DataFrame(a.reshape(-1, len(a)),columns=columns)
print (df)
   age  gender  height  weight  ap_hi  ap_lo  cholesterol  gluc  smoke  alco  \
0   35       2     160      56    120     80            1     1      0     0   

   active  
0       1

If the reshape operation is not clear to read, a more explicit way of adding a dimension to the 1d array is to use numpy.atleast_2d

pd.DataFrame(np.atleast_2d(a), columns=columns)

Or simplier add [] (but slower if really many columns):

df = pd.DataFrame([a],columns=columns)
print (df)
   age  gender  height  weight  ap_hi  ap_lo  cholesterol  gluc  smoke  alco  \
0   35       2     160      56    120     80            1     1      0     0   

   active  
0       1

Thanks Divakar for suggestion:

df = pd.DataFrame(a[None],columns=columns)
print (df)
   age  gender  height  weight  ap_hi  ap_lo  cholesterol  gluc  smoke  alco  \
0   35       2     160      56    120     80            1     1      0     0   

   active  
0       1

And another solution, thanks piRSquared:

pd.DataFrame([a], [0], columns)

edited Jul 26, 2017 at 14:00

baldassarreFe

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answered Jul 26, 2017 at 12:32

jezrael

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2 Comments

Divakar Over a year ago

Shorter one : pd.DataFrame(a[None],columns=columns).

piRSquared Over a year ago

pd.DataFrame([a], [0], columns)

Alex F · Accepted Answer · 2017-07-26 12:37:48Z

1

Just reshape the array to what you need for the dataframe.

import pandas as pd 
import numpy as np

a = np.array([35,2,160,56,120,80,1,1,0,0,1])

columns=['age','gender','height',
 'weight','ap_hi','ap_lo',
 'cholesterol','gluc','smoke',
 'alco','active']

df = pd.DataFrame(np.reshape(a, (1,len(a))),columns=columns)

answered Jul 26, 2017 at 12:37

Alex F

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