rename
Renames one or several columns without changing its location in DataFrame.
df.rename { columns }.into(name)
df.rename { columns }.into { nameExpression }
nameExpression = (DataColumn) -> StringSee column selectors for how to select the columns for this operation.
df.rename { name }.into("fullName")df.rename("name").into("fullName")df.rename { age }.into {
val mean = it.data.mean()
"age [mean = $mean]"
}df.rename("age").into {
val mean = it.data.cast<Int>().mean()
"age [mean = $mean]"
}A special case of rename that renames all column names in a DataFrame to "camelCase" format.
This function standardizes column names by converting them from various naming styles—such as "snake_case", "PascalCase", "kebab-case", or "space delimited formats" into a consistent "camelCase" form.
The transformation follows Kotlin naming conventions for variables and properties, making the resulting column names idiomatic and easier to use in Kotlin code, which is especially useful in extension properties usage.
Use it right after loading raw data to normalize column names into a consistent format. This is especially helpful when preparing the data for further transformations, column access, or integration with Kotlin APIs—making the DataFrame easier and more predictable to work with.
dfRename selected columns to "camelCase":
df.rename { ColumnA and `COLUMN-C` }.toCamelCase()Rename all columns (including nested) to "camelCase":
df.renameToCamelCase()Delimiters (underscores, dashes, spaces, etc.) are removed.
The first word is kept lowercase; all subsequent words are capitalized.
An underscore is inserted between consecutive numbers to improve readability.
If a name contains no letters or digits, it remains unchanged.
Original | camelCase |
|---|---|
hello_world | helloWorld |
HelloWorld | helloWorld |
json.parser.Config | jsonParserConfig |
my.var_name test | myVarNameTest |
thirdColumn | thirdColumn |
someHTMLParser | someHtmlParser |
RESTApi | restApi |
OAuth2Token | oAuth2Token |
GraphQLQuery | graphQlQuery |
TCP_3_PROTOCOL | tcp3Protocol |
123hello_world456 | 123HelloWorld456 |
API_Response_2023 | apiResponse2023 |
UPPER_case-LOWER | upperCaseLower |
12parse34CamelCase | 12Parse34CamelCase |
snake_case_example | snakeCaseExample |
dot.separated.words | dotSeparatedWords |
kebab-case-example | kebabCaseExample |
MIXED_Case_with_123Numbers | mixedCaseWith123Numbers |
!!! | !!! |
1000.2000.3000 | 1000_2000_3000 |
UPPERCASE | uppercase |
alreadyCamelCased | alreadyCamelCased |
justNumbers123 | justNumbers123 |
Just_Special$Chars!! | justSpecialChars |
singleword | singleword |
word_with_underscores_and-dashes | wordWithUnderscoresAndDashes |
10-20-aa | 10_20Aa |