col_vals_str_len()
0.75
0.25
col() with column selectors to specify one or more columns. If multiple columns are supplied or resolved, there will be a separate validation step generated for each column.
`min_val: int | None = None`
The minimum acceptable string length (inclusive). If `None`, no lower bound is applied. At least one of `min_val=` or `max_val=` must be provided.
`max_val: int | None = None`
The maximum acceptable string length (inclusive). If `None`, no upper bound is applied. At least one of `min_val=` or `max_val=` must be provided.
`na_pass: bool = ``False`
Should any encountered None, NA, or Null values be considered as passing test units? By default, this is `False`. Set to `True` to pass test units with missing values.
`pre: Callable | None = None`
An optional preprocessing function or lambda to apply to the data table during interrogation. This function should take a table as input and return a modified table. Have a look at the *Preprocessing* section for more information on how to use this argument.
`segments: SegmentSpec | None = None`
An optional directive on segmentation, which serves to split a validation step into multiple (one step per segment). Can be a single column name, a tuple that specifies a column name and its corresponding values to segment on, or a combination of both (provided as a list). Read the *Segmentation* section for usage information.
`thresholds: int | float | bool | tuple | dict | Thresholds | None = None`
Set threshold failure levels for reporting and reacting to exceedences of the levels. The thresholds are set at the step level and will override any global thresholds set in `Validate(thresholds=...)`. The default is `None`, which means that no thresholds will be set locally and global thresholds (if any) will take effect. Look at the *Thresholds* section for information on how to set threshold levels.
`actions: Actions | None = None`
Optional actions to take when the validation step(s) meets or exceeds any set threshold levels. If provided, the Actions class should be used to define the actions.
`brief: str | bool | None = None`
An optional brief description of the validation step that will be displayed in the reporting table. You can use the templating elements like `"{step}"` to insert the step number, or `"{auto}"` to include an automatically generated brief. If `True` the entire brief will be automatically generated. If `None` (the default) then there won't be a brief.
`active: bool | Callable = ``True`
A boolean value or callable that determines whether the validation step should be active. Using `False` will make the validation step inactive (still reporting its presence and keeping indexes for the steps unchanged). A callable can also be provided; it will receive the data table as its single argument and must return a boolean value. The callable is evaluated *before* any `pre=` processing. Inspection functions like has_columns() and has_rows() can be used here to conditionally activate a step based on properties of the target table.
`dimension: str | None = None`
An optional data quality dimension to categorize this validation step for health scoring. One of `"completeness"`, `"validity"`, `"uniqueness"`, `"consistency"`, `"timeliness"`, or `"volume"` (or any custom string). If `None` (the default), the dimension is inferred automatically from the assertion type. This label appears in the validation report and feeds the overall and per-dimension health scores.
## Returns
`Validate`
The [Validate](Validate.md#pointblank.Validate) object with the added validation step.
## Raises
`ValueError`
If neither `min_val=` nor `max_val=` is provided.
## Examples
For the examples here, we'll use a simple Polars DataFrame with a string column (`a`). The table is shown below:
``` python
import pointblank as pb
import polars as pl
tbl = pl.DataFrame(
{
"a": ["short", "medium str", "a very long string value", "ok"],
}
)
pb.preview(tbl)
```
a
String
|
|
|---|---|
| STEP | COLUMNS | VALUES | TBL | EVAL | UNITS | PASS | FAIL | W | E | C | EXT | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| #4CA64C66 | 1 |
col_vals_str_len()
|
|
✓ | 4 | 3 0.75 |
1 0.25 |
-- | -- | -- | CSV |
| STEP | COLUMNS | VALUES | TBL | EVAL | UNITS | PASS | FAIL | W | E | C | EXT | ||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| #4CA64C66 | 1 |
col_vals_str_len()
|
|
✓ | 4 | 3 0.75 |
1 0.25 |
-- | -- | -- | CSV |