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Pandas: Extract data from MultiIndex levels DataFrame

Pandas Indexing: Exercise-14 with Solution

Write a Pandas program to extract a single row, rows and a specific value from a MultiIndex levels DataFrame.

Sample Solution:

Python Code :

import pandas as pd 
import numpy as np
sales_arrays = [['sale1', 'sale1', 'sale2', 'sale2', 'sale3', 'sale3', '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(sales_tuples)
print("\nConstruct a Dataframe using the said MultiIndex levels: ")
df = pd.DataFrame(np.random.randn(8, 5), index=sales_index)
print(df)

print("\nExtract a single row from the said dataframe:")
print(df.loc[('sale2', 'city2')])
print("\nExtract a single row from the said dataframe:")
print(df.loc[('sale2', 'city2')])

print("\nExtract number of rows from the said dataframe:")
print(df.loc['sale1'])
print("\nExtract number of rows from the said dataframe:")
print(df.loc['sale3'])

print("\nExtract a single value from the said dataframe:")
print(df.loc[('sale1', 'city2'), 1])
print("\nExtract a single value from the said dataframe:")
print(df.loc[('sale4', 'city1'), 4])

Sample Output:

[('sale1', 'city1'), ('sale1', 'city2'), ('sale2', 'city1'), ('sale2', 'city2'), ('sale3', 'city1'), ('sale3', 'city2'), ('sale4', 'city1'), ('sale4', 'city2')]

Construct a Dataframe using the said MultiIndex levels: 
                    0         1         2         3         4
sale  city                                                   
sale1 city1  1.138551  0.507722 -0.870609 -0.186479 -1.038967
      city2 -0.002357  0.227624 -0.146152 -0.185473 -0.741184
sale2 city1 -1.307382  0.846347 -1.011645 -1.354593  2.208438
      city2  0.895843  0.350624  0.674705 -0.920561  0.610004
sale3 city1  0.571192  0.417562 -1.580535 -0.170085  1.258469
      city2  0.455347 -0.285652 -0.632070 -1.259128  0.710763
sale4 city1  0.178355  1.561962  1.627784 -0.097158  1.340233
      city2 -1.211935  0.256773  0.584134  1.505608 -1.559970

Extract a single row from the said dataframe:
0    0.895843
1    0.350624
2    0.674705
3   -0.920561
4    0.610004
Name: (sale2, city2), dtype: float64

Extract a single row from the said dataframe:
0    0.895843
1    0.350624
2    0.674705
3   -0.920561
4    0.610004
Name: (sale2, city2), dtype: float64

Extract number of rows from the said dataframe:
              0         1         2         3         4
city                                                   
city1  1.138551  0.507722 -0.870609 -0.186479 -1.038967
city2 -0.002357  0.227624 -0.146152 -0.185473 -0.741184

Extract number of rows from the said dataframe:
              0         1         2         3         4
city                                                   
city1  0.571192  0.417562 -1.580535 -0.170085  1.258469
city2  0.455347 -0.285652 -0.632070 -1.259128  0.710763

Extract a single value from the said dataframe:
0.22762367059081048

Extract a single value from the said dataframe:
1.340233465712309

Python Code Editor:


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Previous: Write a Pandas program to construct a DataFrame using the MultiIndex levels as the column and index.

Next: Write a Pandas program to rename names of columns and specific labels of the Main Index of the MultiIndex dataframe.

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Python: Tips of the Day

How to sort a Python dict by value

Example:

x1 = {'a': 5, 'b': 7, 'c': 9, 'd': 1}

sorted(x1.items(), key=lambda x: x[1])
[('d', 1), ('c', 9), ('b', 7), ('a', 5)]

# Or:

import operator
print(sorted(x1.items(), key=operator.itemgetter(1)))

Output:

[('d', 1), ('a', 5), ('b', 7), ('c', 9)]