DataFrame.apply

danfo.DataFrame.apply(callable, options)
Parameters
Type
Description
Default
callable
Function
Function to apply to each column or row
​
options
Object
axis: 0 or 1. If 0, compute the power column-wise, if 1, row-wise
{axis: 1}
Examples
Apply a function along default axis 1 (columns)
Note that the specified function passed to apply will be called with an array of the values across the specified axis.
Node
Browser
const dfd = require("danfojs-node")
​
let data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]]
let cols = ["A", "B", "C"]
let df = new dfd.DataFrame(data, { columns: cols })
​
function sum_vals(col) {
    return col.reduce((a, b) => a + b, 0);
}
​
let df_new = df.apply(sum_vals, { axis: 1 })
df_new.print()
​
Output
╔═══╤═════╗
║ 0 │ 6   ║
╟───┼─────╢
║ 1 │ 15  ║
╟───┼─────╢
║ 2 │ 90  ║
╟───┼─────╢
║ 3 │ 206 ║
╚═══╧═════╝
Apply a function along axis 0 (row)
Node
Browser
const dfd = require("danfojs-node")
​
let data = [[1, 2, 3], [4, 5, 6], [20, 30, 40], [39, 89, 78]]
let cols = ["A", "B", "C"]
let df = new dfd.DataFrame(data, { columns: cols })
​
function sum_vals(col) {
    return col.reduce((a, b) => a + b, 0);
}
​
let df_new = df.apply(sum_vals, { axis: 0 })
df_new.print()
​
Output
╔═══╤═════╗
║ A │ 64  ║
╟───┼─────╢
║ B │ 126 ║
╟───┼─────╢
║ C │ 127 ║
╚═══╧═════╝

DataFrame.dropNa

DataFrame.applyMap

Last modified 8mo ago

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Examples

Apply a function along default axis 1 (columns)

Apply a function along axis 0 (row)