PYTHON

Group By

nums = new int[]{1,1,2,3,4,4,4,4,5};
var groupS =nums.GroupBy(x => x);
// for detail view take look at below or click on source link 
// https://leetcode.com/problems/majority-element/discuss/2657752/103-ms-faster-than-97.70-of-C-online-submissions-One-Liner

group a dataset

#DataFrame.groupby() method
e.g
day.groupby('month')

e.g2

day['month'] = day['date_time'].dt.month
by_month = day.groupby('month').mean()
by_month['traffic_volume']

group by

SELECT
  <column_name>,
  COUNT(<column_name>) AS `value_occurrence` 

FROM
  <my_table>

GROUP BY 
  <column_name>

ORDER BY 
  `value_occurrence` DESC

LIMIT 1;

GROUP BY

SELECT <field1, field2, field3…>
FROM <table1_name>
WHERE <condition/expression>
GROUP BY <field1, field2, field3…>

group by

function groupBy(array, keyFn) {
  return array.reduce((accumulator, value) => {
    const key = keyFn(value);
    if (!accumulator[key]) {
      accumulator[key] = [value];
    } else {
      accumulator[key] = [value];
    }
    return accumulator;
  }, {});
}

group by data

import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
dd=pd.melt(df,id_vars=['Group'],value_vars=['Apple','Orange'],var_name='fruits')
sns.boxplot(x='Group',y='value',data=dd,hue='fruits')