API reference
GroupBy
Groupby operations follow the split-apply-combine paradigm. Group a DataFrame or Series, apply an aggregation or transformation, and combine into a result.
| Name | Summary |
|---|---|
DataFrameGroupBy#sum | Compute sum of group values. |
DataFrameGroupBy#mean | Compute mean of groups. |
DataFrameGroupBy#min | Compute minimum of group values. |
DataFrameGroupBy#max | Compute maximum of group values. |
DataFrameGroupBy#count | Compute count of group values. |
DataFrameGroupBy#std | Compute standard deviation of groups. |
DataFrameGroupBy#agg | Aggregate using one or more operations. |
DataFrameGroupBy#transform | Call func producing a like-indexed DataFrame. |
DataFrameGroupBy#filter | Return a copy of a DataFrame excluding elements from groups that do not satisfy |
SeriesGroupBy#sum | Compute sum of groups for a Series. |
SeriesGroupBy#mean | Compute mean of groups for a Series. |
DataFrameGroupBy#sum
#gbdf.sum()Compute sum of group values.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','b','a'], v: [1,2,3] });
df.groupby('g').sum().col('v').to_list(); // => [4, 2]DataFrameGroupBy#mean
#gbdf.mean()Compute mean of groups.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','a','b'], v: [1,3,2] });
df.groupby('g').mean().col('v').to_list(); // => [2, 2]DataFrameGroupBy#min
#gbdf.min()Compute minimum of group values.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','b','a'], v: [1,2,3] });
df.groupby('g').min().col('v').to_list(); // => [1, 2]DataFrameGroupBy#max
#gbdf.max()Compute maximum of group values.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','b','a'], v: [1,2,3] });
df.groupby('g').max().col('v').to_list(); // => [3, 2]DataFrameGroupBy#count
#gbdf.count()Compute count of group values.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','b','a','b','b'], v: [1,2,3,4,5] });
df.groupby('g').count().col('v').to_list(); // => [2, 3]DataFrameGroupBy#std
#gbdf.std(ddof?)Compute standard deviation of groups.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','a','b','b'], v: [1,3,2,4] });
df.groupby('g').std().col('v').to_list(); // => [1.414..., 1.414...]DataFrameGroupBy#agg
#gbdf.agg(func)Aggregate using one or more operations.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','b','a'], v: [1,2,3] });
df.groupby('g').agg({ v: ['sum', 'mean'] }).columns; // => ['v_sum', 'v_mean']DataFrameGroupBy#transform
#gbdf.transform(fn)Call func producing a like-indexed DataFrame.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','a','b'], v: [1,3,2] });
df.groupby('g').transform(s => s.sub(s.mean())).col('v').to_list(); // => [-1, 1, 0]DataFrameGroupBy#filter
#gbdf.filter(fn)Return a copy of a DataFrame excluding elements from groups that do not satisfy the boolean criterion specified by func.
Returns
DataFrame
Example
TypeScript
const df = new DataFrame({ g: ['a','a','b'], v: [1,2,3] });
df.groupby('g').filter(grp => grp.col('v').sum() > 2).col('v').to_list(); // => [1, 2, 3]SeriesGroupBy#sum
#gbs.sum()Compute sum of groups for a Series.
Returns
Series
Example
TypeScript
const s = new Series([1, 2, 3, 4], { index: ['a','b','a','b'] });
s.groupby(s.index).sum().to_list(); // => [4, 6]SeriesGroupBy#mean
#gbs.mean()Compute mean of groups for a Series.
Returns
Series
Example
TypeScript
const s = new Series([1, 3, 2, 4], { index: ['a','a','b','b'] });
s.groupby(s.index).mean().to_list(); // => [2, 3]