## GT.text_transform()
Apply a custom text transformation to cells at specified locations.
Usage
``` python
GT.text_transform(
locations,
fn,
)
```
With the [text_transform()](GT.text_transform.md#great_tables.GT.text_transform) method we can target specific cells and apply a text transformation function to their already-formatted content. This is useful for modifying the rendered text of cells after all formatting (via `fmt_*()` methods) has been applied.
## Parameters
`locations: Loc | list[Loc]`
The cell or set of cells to be associated with the text transformation. Supported locations include [loc.body()](loc.body.md#great_tables.loc.body), [loc.stub()](loc.stub.md#great_tables.loc.stub), [loc.row_groups()](loc.row_groups.md#great_tables.loc.row_groups), and [loc.column_labels()](loc.column_labels.md#great_tables.loc.column_labels).
`fn: Callable[[str], str]`
A function that takes a cell's text content as a string and returns the transformed string.
## Returns
`GT`
The GT object is returned. This is the same object that the method is called on so that we can facilitate method chaining.
## Examples
Let's use the [exibble](data.exibble.md#great_tables.data.exibble) dataset to demonstrate [text_transform()](GT.text_transform.md#great_tables.GT.text_transform). We'll format the `num` column and then apply a text transformation to wrap the values in parentheses.
``` python
from great_tables import GT, loc, exibble
(
GT(exibble[["num", "char"]].head(4))
.fmt_number(columns="num", decimals=1)
.text_transform(
locations=loc.body(columns="num"),
fn=lambda x: f"({x})",
)
)
```
| num | char |
|---------|---------|
| (0.1) | apricot |
| (2.2) | banana |
| (33.3) | coconut |
| (444.4) | durian |
Using [text_transform()](GT.text_transform.md#great_tables.GT.text_transform) we can also convert specific cells to uppercase. Here we target only the first two rows of the `char` column.
``` python
from great_tables import GT, loc, exibble
(
GT(exibble[["num", "char"]].head(4))
.text_transform(
locations=loc.body(columns="char", rows=[0, 1]),
fn=lambda x: x.upper(),
)
)
```
| num | char |
|--------|---------|
| 0.1111 | APRICOT |
| 2.222 | BANANA |
| 33.33 | coconut |
| 444.4 | durian |
Multiple locations can be targeted at once by passing a list. In this example, we add a prefix to all cells in both the `num` and `char` columns.
``` python
from great_tables import GT, loc, exibble
(
GT(exibble[["num", "char"]].head(4))
.fmt_number(columns="num", decimals=2)
.text_transform(
locations=[loc.body(columns="num"), loc.body(columns="char")],
fn=lambda x: f"~ {x}",
)
)
```
| num | char |
|----------|-----------|
| ~ 0.11 | ~ apricot |
| ~ 2.22 | ~ banana |
| ~ 33.33 | ~ coconut |
| ~ 444.40 | ~ durian |