tsb — tsb · isna / notna — Missing Value Detection

Module-level missing-value detection — mirrors pd.isna(), pd.notna(), pd.isnull(), pd.notnull() from pandas.

📝 Code examples

TypeScript

import { isna, notna, isnull, notnull, fillna, dropna, countna, countValid } from "tsb";
import { Series, DataFrame } from "tsb";

// ── scalar ──────────────────────────────────────────────────
console.log(isna(null));          // true
console.log(isna(undefined));     // true
console.log(isna(NaN));           // true
console.log(isna(0));             // false  — zero is not missing
console.log(isna(false));         // false  — false is not missing
console.log(isna(""));            // false  — empty string is not missing

// ── array ───────────────────────────────────────────────────
console.log(isna([1, null, NaN, 3]));     // [false, true, true, false]
console.log(notna([1, null, NaN, 3]));    // [true, false, false, true]

// ── Series ──────────────────────────────────────────────────
const s = new Series({ data: [1, null, NaN, 4] });
console.log(isna(s).values);   // [false, true, true, false]
console.log(notna(s).values);  // [true, false, false, true]

// ── DataFrame ───────────────────────────────────────────────
const df = new DataFrame(new Map([
  ["a", new Series({ data: [1, null, 3] })],
  ["b", new Series({ data: [NaN, 5, 6] })],
]));
console.log(isna(df).col("a").values);  // [false, true, false]
console.log(isna(df).col("b").values);  // [true, false, false]

// ── aliases ─────────────────────────────────────────────────
console.log(isnull(null));   // true  (same as isna)
console.log(notnull(42));    // true  (same as notna)

// ── fillna ──────────────────────────────────────────────────
console.log(fillna([1, null, NaN, 4], { value: 0 }));   // [1, 0, 0, 4]
console.log(fillna(s, { value: -1 }).values);           // [1, -1, -1, 4]
console.log(fillna(df, { value: 0 }).col("b").values);  // [0, 5, 6]

// ── dropna ──────────────────────────────────────────────────
console.log(dropna([1, null, NaN, 3]));   // [1, 3]
console.log(dropna(s).values);            // [1, 4]
console.log(dropna(df).shape);            // [2, 2]  (row 0 dropped because b[0]=NaN, row 1 dropped because a[1]=null)
console.log(dropna(df, { how: "all" }).shape);         // drops only rows where ALL values are missing
console.log(dropna(df, { axis: 1 }).columns.values);  // drops columns that contain any missing value

// ── countna / countValid ─────────────────────────────────────
console.log(countna([1, null, NaN, 3]));    // 2
console.log(countValid([1, null, NaN, 3])); // 2

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