---
title: formatColumns
---

The `formatColumns` method creates a new table containing a new, formula column defining a column format for each argument. It is a special case of [`updateView`](../select/update-view.md) that creates columns that hold format information instead of regular data.

Since `formatColumns` is implemented using `updateView`, the new columns are not stored in memory, and instead a formula is stored that is used to determine the format for each cell/row when necessary.

## Syntax

```
table.formatColumns(columnFormats...)
```

## Parameters

<ParamTable>
<Param name="columnFormats" type="String...">

Formulas to compute formats for columns or rows in the table; e.g., `"X = Y > 5 ? RED : NO_FORMATTING"`.

For color formats, the result of each formula must be either a color string (such as a hexadecimal RGB color, e.g. `"#040427`"), a [Color](/core/javadoc/io/deephaven/gui/color/Color.html), or a packed `long` representation of the background and foreground color (as returned by `bgfg()` or `bgfga()`).

For decimal formats, the result must be a string, and the formula must be wrapped in the special internal function `Decimal()`; e.g., ``"X = Decimal(`$#,##0.00`)"``.

</Param>
</ParamTable>

## Returns

A new table that includes all the original columns from the source table and the newly defined format columns. The format columns are identified internally by the query engine by appending a suffix to the column name.

## Examples

In the following example, column `A` is formatted with a color depending on the value of column `B`, and column `C` is specified to display values as a percentage using the decimal format pattern `0.00%`.

```groovy order=source,result
source = newTable(
    stringCol("A", "The", "At", "Is", "On"),
    intCol("B", 1, 2, 3, 4),
    doubleCol("C", 0.5, 0.66, 0.777, 0.888)
)

result = source.formatColumns(
    "A = B > 2 ? BLUE : NO_FORMATTING",
    "C = Decimal(`0.00%`)"
)
```

## Related documentation

- [How to apply color formatting to columns in a table](../../../how-to-guides/format-columns.md)
- [How to `select`, `view`, and `update` data](../../../how-to-guides/use-select-view-update.md)
- [Javadoc](https://deephaven.io/core/javadoc/io/deephaven/engine/table/Table.html#formatColumns(java.lang.String...))