Expr.log1p

methodView source ↗

def log1p() -> TdExpr

Categories: numeric

Calculate the natural logarithm plus one.

Examples

>>> import tabsdata as td
>>>
>>> tf: td.TableFrame ...
>>>
>>> tf = tf.select(td.col("val"), td.col("val").log1p().alias("log1p")
>>>
┌──────┬──────────┐
│ val  ┆ log1p    │
│ ---  ┆ ---      │
│ f64  ┆ f64      │
╞══════╪══════════╡
│ -1.0 ┆ -inf     │
│ 0.0  ┆ 0.0      │
│ 1.1  ┆ 0.741937 │
│ 2.0  ┆ 1.098612 │
│ inf  ┆ inf      │
│ null ┆ null     │
│ NaN  ┆ NaN      │
└──────┴──────────┘