v0.3.0

This release a number significant additions and bug fixes. Below is a copy of the changelog.

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Bug Fixes

• Fixed define (mutate) and create (transmute), make them work with group_by.
• Fixed tally to work with external arrays.
• Fixed tally to sort in descending order.
• Fixed the nth function of summarize to return NaN when the requested value is out of bounds.
• The contains and matches parameters of select can now accept a tuple of values.
• Fixed verbs that create columns (i.e create, define and do) so that they can create categorical columns.
• The join verbs gained left_on and right_on parameters.
• Fixed verb reuse. You can create a verb and assign it to a variable and pipe to the same variable in different operations.
• Fixed issue where select does maintain the order in which the columns are listed.

New Features

• Added special verb call, it allows one to use external functions that accept a dataframe as the first argument.

• For define, create and group_by, you can now use the special function n() to count the number of elements in current group.

• Added the single table helper verbs:

  • add_count
  • add_tally
  • arrange_all
  • arrange_at
  • arrange_if
  • create_all
  • create_at
  • create_if
  • group_by_all
  • group_by_at
  • group_by_if
  • mutate_all
  • mutate_at
  • mutate_if
  • query_all
  • query_at
  • query_if
  • rename_all
  • rename_at
  • rename_if
  • summarize_all
  • summarize_at
  • summarize_if

• Added pull verb.

• Added slice_rows verb.

API Changes

• Using internal function for summarize that counts the number of elements in the current group changed from {n} to n().
• You can now use piping with the two table verbs (the joins).
• modify_where and define_where helper verbs have been removed. Using the new expression helper functions case_when and if_else is more readable.
• Removed dropna and fillna in favour of using call with pandas.DataFrame.dropna() and pandas.DataFrame.fillna().

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