Pandas count and percentage by value for a column

Pandas count and percentage by value for a column

This is the simplest way to get the count, percenrage ( also from 0 to 100 ) at once with pandas. Let have this data:

food Portion size per 100 grams energy
0 Fish cake 90 cals per cake 200 cals Medium
1 Fish fingers 50 cals per piece 220 cals Medium
2 Gammon 320 cals 280 cals Med-High
3 Haddock fresh 200 cals 110 cals Low calorie
4 Halibut fresh 220 cals 125 cals Low calorie

and we want to find how many items there are per energy:

counts per per100
Medium 14 0.466667 46.7%
High 6 0.200000 20.0%
Med-High 4 0.133333 13.3%
Low calorie 4 0.133333 13.3%
Low- Med 1 0.033333 3.3%
Low-Med 1 0.033333 3.3%

This sample code will give you:

  • counts for each value in the column
  • percentage of occurrences for each value
  • pecentange format from 0 to 100 and adding % sign

First we are going to read external data as pdf:

from tabula import read_pdf
import pandas as pd
df = read_pdf("http://www.uncledavesenterprise.com/file/health/Food%20Calories%20List.pdf", pages=3, pandas_options={'header': None})
df.columns = ['food', 'Portion size ', 'per 100 grams', 'energy']
df.head()

Then we are going to calculate the count and percent:

s = df.keywords
counts = s.value_counts()
percent = s.value_counts(normalize=True)
percent100 = s.value_counts(normalize=True).mul(100).round(1).astype(str) + '%'
pd.DataFrame({'counts': counts, 'per': percent, 'per100': percent100})

pandas_value_count_percent

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