Migration to 1.0

Deprecations and removals

As we move toward version 1.0, many functions have been changed, deprecated, or removed. This section provides a complete overview of all API changes to help you migrate to 1.0.

Renamed functions and classes to the correct CamelCase spelling

All functions and classes in Kotlin DataFrame have been renamed to the correct CamelCase spelling.

See below for a complete list of the renamed functions and classes.

Migration to Deephaven CSV

All CSV (as well as TSV) IO was migrated to a new, fast, and efficient Deephaven CSV implementation. It significantly improves CSV IO performance and brings many new parametrization options.

All related methods are now located in the separate dataframe-csv module (which is included by default in the general dataframe artifact and in %use dataframe in Kotlin Notebook).

Functions were also renamed to the correct CamelCase spelling.

All new functions keep the same arguments as before and additionally introduce new ones. Also, there are new arguments that expose Deephaven CSV features.

See Read from CSV.

0.15	1.0
`CSV`/`TSV`	`CsvDeephaven`/`TsvDeephaven`
`DataFrame.readCSV(..)`/`DataFrame.readTSV(..)`	`DataFrame.readCsv(..)`/`DataFrame.readTsv(..)`
`DataFrame.read(delimeter=.., ..)`	`DataFrame.readCsv(delimeter=.., ..)`
`df.writeCSV(..)`/`df.writeTSV(..)`	`df.writeCsv(..)`/`df.writeTsv(..)`
`df.toCSV(..)`	`df.toCsvStr(..)`

Migration to Standard Library `Instant`

Since Kotlin 2.1.20, Instant is now part of the standard library
(as kotlin.time.Instant). You can still use the old (deprecated) kotlinx.datetime.Instant type, but its support will be removed in Kotlin DataFrame 1.1.

For now, each Instant-related operation has been split into two new ones — one for the new stdlib kotlin.time.Instant and one for the old deprecated kotlinx.datetime.Instant. The behavior of old operations remains unchanged: they work with kotlinx.datetime.Instant and raise ERROR in 1.0. In version 1.1, they will be returned and will operate on the new stdlib kotlin.time.Instant.

0.15	1.0	Note
`col.convertToInstant()`	`col.convertToDeprecatedInstant()`	`WARNING` in 1.0, `ERROR` in 1.1
`col.convertToInstant()`	`col.convertToStdlibInstant()`	Will be renamed back into `convertToInstant() in 1.1`
`df.convert { columns }.toInstant()`	`df.convert { columns }.convertToDeprecatedInstant()`	`WARNING` in 1.0, `ERROR` in 1.1
`df.convert { columns }.toInstant()`	`df.convert { columns }.convertToStdlibInstant()`	Will be renamed back into `convertToInstant() in 1.1`
`ColType.Instant`	`ColType.DeprecatedInstant`	`WARNING` in 1.0, `ERROR` in 1.1
`ColType.Instant`	`ColType.StdlibInstant`	Will be renamed back into `Instant` in 1.1

In version 1.0, all parsing operations still convert Instant values into the deprecated kotlinx.datetime.Instant. To enable parsing into the new standard library kotlin.time.Instant, set the corresponding parsing option ParserOptions.parseExperimentalInstant (that will be default in 1.1). For example:

DataFrame.readCsv(
    ...,
    parserOptions = ParserOptions(parseExperimentalInstant = true)
)

Deprecation of `cols()` and other methods in Columns Selection DSL

cols() overloads without arguments, which select all columns of a DataFrame or all subcolumns inside a column group in the Columns Selection DSL, are deprecated in favor of all() and allCols() respectively. These replacements allow the Compiler Plugin to fully support such selections.

colsAtAnyDepth(), colsInGroups(), and single() overloads with a predicate argument that filters columns are also deprecated for better Compiler Plugin support. Use .filter(predicate) for filtering instead.

0.15	1.0
`df.select { cols() }`	`df.select { all() }`
`df.select { colGroup.cols() }`	`df.select { colGroup.allCols() }`
`df.select { colsAtAnyDepth { predicate } }`	`df.select { colsAtAnyDepth().filter { predicate } }`
`df.select { colsInGroups { predicate } }`	`df.select { colsInGroups().filter { predicate } }`
`df.select { single { predicate } }`	`df.select { cols().filter { predicate }.single() }`
`df.select { colGroup.singleCol { predicate } }`	`df.select { colGroup.allCols().filter { predicate }.single() }`
`df.select { colSet.single { predicate } }`	`df.select { colSet.filter { predicate }.single() }`

Removed functions and classes

The next functions and classes raise ERROR in 1.0 and will be removed in 1.1.

0.15	1.0	Reason
`DataColumn.createFrameColumn(name, df, startIndices)`	`df.chunked(name, startIndices)`	Replaced with another function.
`DataColumn.createWithTypeInference(name, values, nullable)`	`DataColumn.createByInference(name, values, TypeSuggestion.Infer, nullable)`	Replaced with another function.
`DataColumn.create(name, values, infer)`	`DataColumn.createByType(name, values, infer)`	Replaced with another function.
`col.isComparable()`	`col.valuesAreComparable()`	Renamed to better reflect its purpose.
`df.minus { columns }`	`df.remove { columns }`	Replaced with another function.
`df.move { columns }.toLeft()`/`df.moveToLeft{ columns }`	`df.move { columns }.toStart()`/`df.moveToStart { columns }`	Renamed to better reflect its purpose.
`df.move { columns }.toRight()`/`df.moveToRight{ columns }`	`df.move { columns }.toEnd()`/`df.moveToEnd{ columns }`	Renamed to better reflect its purpose.
`row.rowMin()`/`row.rowMinOrNull()`	`row.rowMinOf()`/`row.rowMinOfOrNull()`	Renamed to better reflect its purpose.
`row.rowMax()`/`row.rowMaxOrNull()`	`row.rowMaxOf()`/`AnyRow.rowMaxOfOrNull()`	Renamed to better reflect its purpose.
`row.rowPercentile()`/`row.rowPercentileOrNull()`	`row.rowPercentileOf()`/`row.rowPercentileOfOrNull()`	Renamed to better reflect its purpose.
`row.rowMedian()`/`row.rowMedianOrNull()`	`row.rowMedianOf()`/`row.rowMedianOfOrNull()`	Renamed to better reflect its purpose.
`df.convert { columns }.to { converter }`	`df.convert { columns }.asColumn { converter }`	Renamed to better reflect its purpose.
`df.toHTML(..)`/`df.toStandaloneHTML()`	`df.toHtml(..)`/`df.toStandaloneHtml()`	Renamed to the correct CamelCase.
`df.writeHTML()`	`df.writeHtml()`	Renamed to the correct CamelCase.
`asURL(fileOrUrl)`/`isURL(path)`	`asUrl(fileOrUrl)`/`isUrl(path)`	Renamed to the correct CamelCase.
`df.convert { columns }.toURL()`/`df.convertToURL { columns }`	`df.convert { columns }.toUrl()`/`df.convertToUrl { columns }`	Renamed to the correct CamelCase.
`df.filterBy(column)`	`df.filter { column }`	Replaced with another function.
`FormattingDSL`	`FormattingDsl`	Renamed to the correct CamelCase.
`RGBColor`	`RgbColor`	Renamed to the correct CamelCase.
`df.insert(column).after(columnPath)`	`df.insert(column).after { columnPath }`	Replaced with another function.
`CompareResult.Equals`/`CompareResult.isEqual()`	`CompareResult.Matches`/`CompareResult.matches()`	Renamed to better reflect its purpose.
`CompareResult.isSuperOrEqual()`	`CompareResult.isSuperOrMatches()`	Renamed to better reflect its purpose.

The next functions and classes raise WARNING in 1.0 and ERROR in 1.1.

0.15	1.0	Reason
`df.split { columns }.default(..)`/`df.split { columns }.into(..)`/`df.split { columns }.inward(..)`	`df.split { columns }.by(..).default(..)`/`df.split { columns }.by(..).into(..)`/`df.split { columns }.by(..).inward(..)`	Removed a shortcut to clarify the behaviour; Only for `String` columns.
`dataFrameOf(header, values)`	`dataFrameOf(header).withValues(values)`	Replaced with another function.
`df.generateCode(..)`	`df.generateInterfaces(..)`	Replaced with another function.
`df.select { mapToColumn(name, infer) { body } }`	`df.select { expr(name, infer) { body } }`	Removed duplicated functionality.
`stringCol.length()`	`stringCol.map { it?.length ?: 0 }`	Removed a shortcut to clarify the behaviour; Only for `String` columns.
`stringCol.lowercase()`/`stringCol.uppercase()`	`stringCol.map { it?.lowercase() }`/`stringCol.map { it?.uppercase() }`	Removed a shortcut to clarify the behaviour; Only for `String` columns.
`df.add(columns)`/`df.add(dataframes)`	`df.addAll(columns)`/`df.addAll(dataframes)`	Renamed to to improve completion.
`row.isEmpty()`/`row.isNotEmpty()`	`row.values().all { it == null }`/`row.values().all { it == null }`	Removed a shortcut to clarify the behaviour;
`row.getRow(index)`/`row.getRowOrNull(index)`/`row.getRows(indices)`	`row.df().getRow(index)`/`row.df().getRowOrNull(index)`/`row.df().getRows(indices)`	Removed a shortcut to clarify the behaviour;
`df.copy()`	`df.columns().toDataFrame().cast()`	Removed a shortcut to clarify the behaviour;
`KeyValueProperty<T>`	`NameValueProperty<T>`	Removed duplicated functionality.

19 December 2025