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Version: Java (Groovy)

updateView

The updateView method creates a new table containing a new, formula column for each argument.

When using updateView, the new columns are not stored in memory. Rather, a formula is stored that is used to recalculate each cell every time it is accessed.

note

The syntax for the updateView, update, and lazyUpdate methods is identical, as is the resulting table. updateView is recommended when:

  1. the formula is fast to compute,
  2. only a small portion of the data is being accessed,
  3. cells are accessed very few times, or
  4. memory usage must be minimized.

For other cases, consider using select, view, update, or lazyUpdate. These methods have different memory and computation expenses.

caution

When using view or updateView, non-deterministic methods (e.g., random numbers, current time, or mutable structures) produce unstable results. Downstream operations on these results produce undefined behavior. Non-deterministic methods should use select or update instead.

Syntax​

table.updateView(columns...)

Parameters​

ParameterTypeDescription
columnsString...

Formulas to compute columns in the new table; e.g., "X = A * sqrt(B)".

columnsCollection<? extends Selectable>

Formulas to compute columns in the new table; e.g., "X = A * sqrt(B)".

Returns​

A new table that includes all the original columns from the source table and the newly defined formula columns.

Examples​

In the following example, a new table containing the columns from the source table plus two new columns, X and Y, is created.

source = newTable(
    stringCol("A", "The", "At", "Is", "On"),
    intCol("B", 1, 2, 3, 4),
    intCol("C", 5, 6, 7, 8)
)

result = source.updateView("X = B", "Y = sqrt(C)")