Finding

Files
file	find.hpp
file	find_multiple.hpp

Functions
std::unique_ptr< column >	cudf::strings::find (strings_column_view const &strings, string_scalar const &target, size_type start=0, size_type stop=-1, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of character position values where the target string is first found in each string of the provided column. More...
std::unique_ptr< column >	cudf::strings::rfind (strings_column_view const &strings, string_scalar const &target, size_type start=0, size_type stop=-1, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of character position values where the target string is first found searching from the end of each string. More...
std::unique_ptr< column >	cudf::strings::contains (strings_column_view const &strings, string_scalar const &target, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates the target string was found within that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::contains (strings_column_view const &strings, strings_column_view const &targets, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates the corresponding target string was found within that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::starts_with (strings_column_view const &strings, string_scalar const &target, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates the target string was found at the beginning of that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::starts_with (strings_column_view const &strings, strings_column_view const &targets, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates corresponding string in target column was found at the beginning of that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::ends_with (strings_column_view const &strings, string_scalar const &target, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates the target string was found at the end of that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::ends_with (strings_column_view const &strings, strings_column_view const &targets, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a column of boolean values for each string where true indicates corresponding string in target column was found at the end of that string in the provided column. More...
std::unique_ptr< column >	cudf::strings::find_multiple (strings_column_view const &input, strings_column_view const &targets, rmm::mr::device_memory_resource *mr=rmm::mr::get_current_device_resource())
	Returns a lists column with character position values where each of the target strings are found in each string. More...

Detailed Description

Function Documentation

contains() [1/2]

std::unique_ptr<column> cudf::strings::contains	(	strings_column_view const &	strings,
		string_scalar const &	target,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates the target string was found within that string in the provided column.

If the target is not found for a string, false is returned for that entry in the output column. If target is an empty string, true is returned for all non-null entries in the output column.

Any null string entries return corresponding null entries in the output columns.

Parameters

strings	Strings instance for this operation.
target	UTF-8 encoded string to search for in each string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.

contains() [2/2]

std::unique_ptr<column> cudf::strings::contains	(	strings_column_view const &	strings,
		strings_column_view const &	targets,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates the corresponding target string was found within that string in the provided column.

The 'output[i] = trueif stringtargets[i]is found insidestrings[i]otherwise output[i] = false. Iftarget[i]is an empty string, true is returned foroutput[i]. Iftarget[i]is null, false is returned foroutput[i]`.

Any null strings[i] row results in a null output[i] row.

Exceptions

cudf::logic_error

if strings.size() != targets.size().

Parameters

strings	Strings instance for this operation.
targets	Strings column of targets to check row-wise in strings.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.

ends_with() [1/2]

std::unique_ptr<column> cudf::strings::ends_with	(	strings_column_view const &	strings,
		string_scalar const &	target,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates the target string was found at the end of that string in the provided column.

If target is not found at the end of a string, false is set for that row entry in the output column. If target is an empty string, true is returned for all non-null entries in the output column.

Any null string entries return corresponding null entries in the output columns.

Parameters

strings	Strings instance for this operation.
target	UTF-8 encoded string to search for in each string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.

ends_with() [2/2]

std::unique_ptr<column> cudf::strings::ends_with	(	strings_column_view const &	strings,
		strings_column_view const &	targets,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates corresponding string in target column was found at the end of that string in the provided column.

If targets[i] is not found at the end of a string in strings[i], false is set for that row entry in the output column. If targets[i] is an empty string, true is returned for the corresponding entry in the output column.

Any null string entries in targets return corresponding null entries in the output columns.

Exceptions

cudf::logic_error

if strings.size() != targets.size().

Parameters

strings	Strings instance for this operation.
targets	Strings instance for this operation.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.

find()

std::unique_ptr<column> cudf::strings::find	(	strings_column_view const &	strings,
		string_scalar const &	target,
		size_type	start = 0,
		size_type	stop = -1,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of character position values where the target string is first found in each string of the provided column.

If target is not found, -1 is returned for that row entry in the output column.

The target string is searched within each string in the character position range [start,stop). If the stop parameter is -1, then the end of each string becomes the final position to include in the search.

Any null string entries return corresponding null output column entries.

Exceptions

cudf::logic_error

if start position is greater than stop position.

Parameters

strings	Strings instance for this operation.
target	UTF-8 encoded string to search for in each string.
start	First character position to include in the search.
stop	Last position (exclusive) to include in the search. Default of -1 will search to the end of the string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New integer column with character position values.

find_multiple()

std::unique_ptr<column> cudf::strings::find_multiple	(	strings_column_view const &	input,
		strings_column_view const &	targets,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a lists column with character position values where each of the target strings are found in each string.

The size of the output column is input.size(). Each row of the output column is of size targets.size().

output[i,j] contains the position of targets[j] in input[i]

Example:
s = ["abc", "def"]
t = ["a", "c", "e"]
r = find_multiple(s, t)
r is now {[ 0, 2,-1],   // for "abc": "a" at pos 0, "c" at pos 2, "e" not found
          [-1,-1, 1 ]}  // for "def": "a" and "b" not found, "e" at  pos 1

Exceptions

cudf::logic_error

if targets is empty or contains nulls

Parameters

input	Strings instance for this operation.
targets	Strings to search for in each string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

Lists column with character position values.

rfind()

std::unique_ptr<column> cudf::strings::rfind	(	strings_column_view const &	strings,
		string_scalar const &	target,
		size_type	start = 0,
		size_type	stop = -1,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of character position values where the target string is first found searching from the end of each string.

If target is not found, -1 is returned for that entry.

The target string is searched within each string in the character position range [start,stop). If the stop parameter is -1, then the end of each string becomes the final position to include in the search.

Any null string entries return corresponding null output column entries.

Exceptions

cudf::logic_error

if start position is greater than stop position.

Parameters

strings	Strings instance for this operation.
target	UTF-8 encoded string to search for in each string.
start	First position to include in the search.
stop	Last position (exclusive) to include in the search. Default of -1 will search starting at the end of the string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New integer column with character position values.

starts_with() [1/2]

std::unique_ptr<column> cudf::strings::starts_with	(	strings_column_view const &	strings,
		string_scalar const &	target,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates the target string was found at the beginning of that string in the provided column.

If target is not found at the beginning of a string, false is set for that row entry in the output column. If target is an empty string, true is returned for all non-null entries in the output column.

Any null string entries return corresponding null entries in the output columns.

Parameters

strings	Strings instance for this operation.
target	UTF-8 encoded string to search for in each string.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.

starts_with() [2/2]

std::unique_ptr<column> cudf::strings::starts_with	(	strings_column_view const &	strings,
		strings_column_view const &	targets,
		rmm::mr::device_memory_resource *	mr = rmm::mr::get_current_device_resource()
	)

Returns a column of boolean values for each string where true indicates corresponding string in target column was found at the beginning of that string in the provided column.

If targets[i] is not found at the beginning of a string in strings[i], false is set for that row entry in the output column. If targets[i] is an empty string, true is returned for corresponding entry in the output column.

Any null string entries in targets return corresponding null entries in the output columns.

Exceptions

cudf::logic_error

if strings.size() != targets.size().

Parameters

strings	Strings instance for this operation.
targets	Strings instance for this operation.
mr	Device memory resource used to allocate the returned column's device memory.

Returns

New type_id::BOOL8 column.