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Version: Python

format_columns

The format_columns method creates a new table containing a new, formula column defining a column format for each argument. It is a special case of update_view that creates columns that hold format information instead of regular data.

Since format_columns is implemented using update_view, 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.format_columns(column_formats: Union[str, list[str]]) -> Table

Parameters​

ParameterTypeDescription
column_formatsUnion[str, list[str]]

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, 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`)".

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, the 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%.

from deephaven import new_table
from deephaven.column import int_col, double_col, string_col

source = new_table(
    [
        string_col("A", ["The", "At", "Is", "On"]),
        int_col("B", [1, 2, 3, 4]),
        double_col("C", [0.5, 0.66, 0.777, 0.888]),
    ]
)

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