turi::dataframe_row_iterator Class Reference

#include <core/storage/sframe_data/dataframe.hpp>

Public Member Functions
void	swap_column_order (size_t a, size_t b)
dataframe_row_iterator &	operator++ ()
	pre-increments to the next entry of the dataframe row-wise
dataframe_row_iterator &	operator++ (int)
	post-increments to the next entry of the dataframe row-wise
size_t	row () const
	Returns the index of the current row.
size_t	column () const
	Returns the index of the current column.
size_t	column_size () const
	Returns the number of columns.
size_t	row_size () const
	Returns the number of rows.
const std::string &	column_name () const
	Returns the name of the current column.
const std::string &	column_name (size_t idx) const
	Returns the name of an arbitrary column.
const std::vector< std::string > &	column_names () const
	Returns the list of all column names.
flex_type_enum	column_type () const
	Returns the type of the current column.
flex_type_enum	column_type (size_t idx) const
	Returns the type of an arbitrary column.
const std::vector< flex_type_enum > &	column_types () const
	Returns the list of all column types.
void	skip_rows (size_t num_rows_to_skip)
bool	operator== (const dataframe_row_iterator &other)
	Returns true if both iterators are equal.
bool	operator!= (const dataframe_row_iterator &other)
	Returns true if both iterators are not equal.
const flexible_type &	operator* ()
	Dereferences the iterator, returning a reference to the underlying flexible_type.
const flexible_type &	operator* () const
	Dereferences the iterator, returning a reference to the underlying flexible_type.
const flexible_type *	operator-> ()
	Dereferences the iterator, returning a reference to the underlying flexible_type.
const flexible_type *	operator-> () const
	Dereferences the iterator, returning a reference to the underlying flexible_type.

Static Public Member Functions
static dataframe_row_iterator	begin (const dataframe_t &dt)
	Creates a begin iterator to the dataframe.
static dataframe_row_iterator	end (const dataframe_t &dt)
	Creates an end iterator to the dataframe.

Detailed Description

The dataframe is a column-wise representation. This provides iteration over the dataframe in a row-wise representation. Incrementing the iterator advances the iterator element by element by across rows.

Usage:

// Performs a row-wise iteration over the entries of the dataframe
dataframe_row_iterator iter = dataframe_row_iterator::begin(df);
dataframe_row_iterator end = dataframe_row_iterator::end(df);
while (iter != end) {
  // do stuff with (*iter). It is a flexible_type
  ++iter;
}

// Alternatively:
dataframe_row_iterator iter = dataframe_row_iterator::begin(df);
for (size_t row = 0; row < iter.row_size(); ++row) {
  for (size_t col = 0; col < iter.col_size(); ++col) {
    // do stuff with (*iter). It is a flexible_type
    // pointing to the cell in column 'col' and row 'row'
    ++iter;
  }
}

Definition at line 205 of file dataframe.hpp.

Member Function Documentation

skip_rows()

void turi::dataframe_row_iterator::skip_rows

(

size_t

num_rows_to_skip

)

Advances the iterator by this number of rows. Current column does not change. If the number of rows to skip causes the iterator to go past the end of the dataframe, the resultant iterator is equivalent to the end iterator of the dataframe.

swap_column_order()

void turi::dataframe_row_iterator::swap_column_order ( size_t  a, size_t  b  )

inline

Changes the column iterator ordering by swapping the indices of columns 'a' and columns 'b'. Should only be done on begin and end iterators. Iterators in the midst of iterating are not safe to be swapped.

Definition at line 248 of file dataframe.hpp.

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The documentation for this class was generated from the following file:

• core/storage/sframe_data/dataframe.hpp