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Pandas: Extract elements in the given positional indices along an axis of a DataFrame

Pandas Indexing: Exercise-17 with Solution

Write a Pandas program to extract elements in the given positional indices along an axis of a dataframe.

Sample Solution:

Python Code :

import pandas as pd 
import numpy as np
sales_arrays = [['sale1', 'sale1', 'sale3', 'sale3', 'sale2', 'sale2', 'sale4', 'sale4'],
          ['city1', 'city2', 'city1', 'city2', 'city1', 'city2', 'city1', 'city2']]
sales_tuples = list(zip(*sales_arrays))
sales_index = pd.MultiIndex.from_tuples(sales_tuples, names=['sale', 'city'])
print("\nConstruct a Dataframe using the said MultiIndex levels:")
df = pd.DataFrame(np.random.randn(8, 5), index=sales_index)
print(df)
print("\nSelect 1st, 2nd and 3rd row of the said DataFrame:")
positions = [1, 2, 5]
print(df.take([1, 2, 5]))

print("\nTake elements at indices 1 and 2 along the axis 1 (column selection):")
print(df.take([1, 2], axis=1))

print("\nTake elements at indices 4 and 3 using negative integers along the axis 1 (column selection):")
print(df.take([-1, -2], axis=1))

Sample Output:

Construct a Dataframe using the said MultiIndex levels:
                    0         1         2         3         4
sale  city                                                   
sale1 city1  0.913076  0.354532 -0.802093  0.791970 -0.218581
      city2  1.142819 -0.368298  0.215453  0.026137 -0.890050
sale3 city1  0.252533 -0.573312  0.063797  0.785013 -1.089888
      city2 -0.289990  0.122610 -1.694256  0.375177 -1.724325
sale2 city1 -0.369298  0.298590 -1.003860 -0.105213  0.157668
      city2  1.596571  0.010428 -1.182087  0.247076 -0.602570
sale4 city1 -0.060375  1.958592 -1.628266 -0.081583 -0.364392
      city2  0.846199  0.284048  0.799424 -1.486897  0.633890

Select 1st, 2nd and 3rd row of the said DataFrame:
                    0         1         2         3         4
sale  city                                                   
sale1 city2  1.142819 -0.368298  0.215453  0.026137 -0.890050
sale3 city1  0.252533 -0.573312  0.063797  0.785013 -1.089888
sale2 city2  1.596571  0.010428 -1.182087  0.247076 -0.602570

Take elements at indices 1 and 2 along the axis 1 (column selection):
                    1         2
sale  city                     
sale1 city1  0.354532 -0.802093
      city2 -0.368298  0.215453
sale3 city1 -0.573312  0.063797
      city2  0.122610 -1.694256
sale2 city1  0.298590 -1.003860
      city2  0.010428 -1.182087
sale4 city1  1.958592 -1.628266
      city2  0.284048  0.799424

Take elements at indices 4 and 3 using negative integers along the axis 1 (column selection):
                    4         3
sale  city                     
sale1 city1 -0.218581  0.791970
      city2 -0.890050  0.026137
sale3 city1 -1.089888  0.785013
      city2 -1.724325  0.375177
sale2 city1  0.157668 -0.105213
      city2 -0.602570  0.247076
sale4 city1 -0.364392 -0.081583
      city2  0.633890 -1.486897

Python Code Editor:


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