csv Namespace Reference

The all encompassing namespace. More...

Namespaces
	internals
	Stuff that is generally not of interest to end-users.

Classes
struct	CSVGuessResult
	Stores the inferred format of a CSV file. More...
class	CSVFormat
	Stores information about how to parse a CSV file. More...
class	CSVReader
	Main class for parsing CSVs from files and in-memory sources. More...
class	CSVField
	Data type representing individual CSV values. More...
class	CSVRow
	Data structure for representing CSV rows. More...
class	CSVStat
	Class for calculating statistics from CSV files and in-memory sources. More...
struct	CSVFileInfo
	Returned by get_file_info() More...
class	DelimWriter
	Class for writing delimiter separated values files. More...

Typedefs
using	RowCollection = internals::ThreadSafeDeque< CSVRow >
	Standard type for storing collection of rows.
using	string_view = nonstd::string_view
	The string_view class used by this library.
template<bool B, class T = void>
using	enable_if_t = typename std::enable_if< B, T >::type

Enumerations
enum class	VariableColumnPolicy { THROW = -1 , IGNORE_ROW = 0 , KEEP = 1 }
	Determines how to handle rows that are shorter or longer than the majority.
enum class	DataType {   UNKNOWN = -1 , CSV_NULL , CSV_STRING , CSV_INT8 ,   CSV_INT16 , CSV_INT32 , CSV_INT64 , CSV_BIGINT ,   CSV_DOUBLE }
	Enumerates the different CSV field types that are recognized by this library. More...

Functions
std::vector< std::string >	get_col_names (csv::string_view filename, CSVFormat format)
	Return a CSV's column names. More...
CSVGuessResult	guess_format (csv::string_view filename, const std::vector< char > &delims)
	Guess the delimiter used by a delimiter-separated values file.
	CSVRow::operator std::vector< std::string > () const
	HEDLEY_NON_NULL (2) CSVRow
template<>
std::string	CSVField::get< std::string > ()
	Retrieve this field's original string.
template<>
CONSTEXPR_14 csv::string_view	CSVField::get< csv::string_view > ()
	Retrieve a view over this field's string. More...
Utility Functions
std::unordered_map< std::string, DataType >	csv_data_types (const std::string &filename)
	Useful for uploading CSV files to SQL databases. More...
int	get_col_pos (csv::string_view filename, csv::string_view col_name, const CSVFormat &format)
	Find the position of a column in a CSV file or CSV_NOT_FOUND otherwise. More...
CSVFileInfo	get_file_info (const std::string &filename)
	Get basic information about a CSV file. More...
Shorthand Parsing Functions
Convienience functions for parsing small strings
CSVReader	parse (csv::string_view in, CSVFormat format)
	Shorthand function for parsing an in-memory CSV string. More...
CSVReader	parse_no_header (csv::string_view in)
	Parses a CSV string with no headers. More...
CSVReader	operator""_csv (const char *in, size_t n)
	Parse a RFC 4180 CSV string, returning a collection of CSVRow objects. More...
CSVReader	operator""_csv_no_header (const char *in, size_t n)
	A shorthand for csv::parse_no_header()

Variables
constexpr int	CSV_NOT_FOUND = -1
	Integer indicating a requested column wasn't found.

CSV Writing
template<class OutputStream , bool Flush = true>
using	CSVWriter = DelimWriter< OutputStream, ',', '"', Flush>
	An alias for csv::DelimWriter for writing standard CSV files. More...
template<class OutputStream , bool Flush = true>
using	TSVWriter = DelimWriter< OutputStream, '\t', '"', Flush>
	Class for writing tab-separated values files. More...
template<class OutputStream >
CSVWriter< OutputStream >	make_csv_writer (OutputStream &out, bool quote_minimal=true)
	Return a csv::CSVWriter over the output stream.
template<class OutputStream >
CSVWriter< OutputStream, false >	make_csv_writer_buffered (OutputStream &out, bool quote_minimal=true)
	Return a buffered csv::CSVWriter over the output stream (does not auto flush)
template<class OutputStream >
TSVWriter< OutputStream >	make_tsv_writer (OutputStream &out, bool quote_minimal=true)
	Return a csv::TSVWriter over the output stream.
template<class OutputStream >
TSVWriter< OutputStream, false >	make_tsv_writer_buffered (OutputStream &out, bool quote_minimal=true)
	Return a buffered csv::TSVWriter over the output stream (does not auto flush)

Detailed Description

The all encompassing namespace.

Typedef Documentation

CSVWriter

template<class OutputStream , bool Flush = true>

using csv::CSVWriter = typedef DelimWriter<OutputStream, ',', '"', Flush>

An alias for csv::DelimWriter for writing standard CSV files.

See also

csv::DelimWriter::operator<<()

Note

Use csv::make_csv_writer() to in instatiate this class over an actual output stream.

Definition at line 375 of file csv_writer.hpp.

TSVWriter

template<class OutputStream , bool Flush = true>

using csv::TSVWriter = typedef DelimWriter<OutputStream, '\t', '"', Flush>

Class for writing tab-separated values files.

See also

csv::DelimWriter::write_row()

csv::DelimWriter::operator<<()

Note

Use csv::make_tsv_writer() to in instatiate this class over an actual output stream.

Definition at line 386 of file csv_writer.hpp.

Enumeration Type Documentation

DataType

enum csv::DataType

strong

Enumerates the different CSV field types that are recognized by this library.

Note

Overflowing integers will be stored and classified as doubles.

Unlike previous releases, integer enums here are platform agnostic.

Enumerator
CSV_NULL	Empty string.
CSV_STRING	Non-numeric string.
CSV_INT8	8-bit integer
CSV_INT16	16-bit integer (short on MSVC/GCC)
CSV_INT32	32-bit integer (int on MSVC/GCC)
CSV_INT64	64-bit integer (long long on MSVC/GCC)
CSV_BIGINT	Value too big to fit in a 64-bit in.
CSV_DOUBLE	Floating point value.

Definition at line 20 of file data_type.hpp.

Function Documentation

csv_data_types()

std::unordered_map< std::string, DataType > csv::csv_data_types

(

const std::string &

filename

)

Useful for uploading CSV files to SQL databases.

Return a data type for each column such that every value in a column can be converted to the corresponding data type without data loss.

Parameters

[in]

filename

The CSV file

Returns

A mapping of column names to csv::DataType enums

Definition at line 240 of file csv_stat.cpp.

CSVField::get< csv::string_view >()

template<>

CONSTEXPR_14 csv::string_view csv::CSVField::get< csv::string_view >

(

)

Retrieve a view over this field's string.

Warning

This string_view is only guaranteed to be valid as long as this CSVRow is still alive.

Definition at line 425 of file csv_row.hpp.

get_col_names()

std::vector< std::string > csv::get_col_names	(	csv::string_view	filename,
		CSVFormat	format
	)

Return a CSV's column names.

Parameters

[in]	filename	Path to CSV file
[in]	format	Format of the CSV file

Guess delimiter and header row

Definition at line 125 of file csv_reader.cpp.

get_col_pos()

int csv::get_col_pos	(	csv::string_view	filename,
		csv::string_view	col_name,
		const CSVFormat &	format
	)

Find the position of a column in a CSV file or CSV_NOT_FOUND otherwise.

Parameters

[in]	filename	Path to CSV file
[in]	col_name	Column whose position we should resolve
[in]	format	Format of the CSV file

Definition at line 53 of file csv_utility.cpp.

get_file_info()

CSVFileInfo csv::get_file_info

(

const std::string &

filename

)

Get basic information about a CSV file.

#include "csv.hpp"
#include <iostream>
 
int main(int argc, char** argv) {
    using namespace csv;
 
    if (argc < 2) {
        std::cout << "Usage: " << argv[0] << " [file]" << std::endl;
        exit(1);
    }
 
    std::string file = argv[1];
    auto info = get_file_info(file);
 
    std::cout << file << std::endl
        << "Columns: " << internals::format_row(info.col_names, ", ")
        << "Dimensions: " << info.n_rows << " rows x " << info.n_cols << " columns" << std::endl
        << "Delimiter: " << info.delim << std::endl;
 
    return 0;
}

Definition at line 64 of file csv_utility.cpp.

operator""_csv()

CSVReader csv::operator""_csv	(	const char *	in,
		size_t	n
	)

Parse a RFC 4180 CSV string, returning a collection of CSVRow objects.

Example

TEST_CASE( "Test Escaped Comma", "[read_csv_comma]" ) {
    auto rows = "A,B,C\r\n" // Header row
                "123,\"234,345\",456\r\n"
                "1,2,3\r\n"
                "1,2,3"_csv;
 
    CSVRow row;
    rows.read_row(row);
    REQUIRE( vector<string>(row) == 
        vector<string>({"123", "234,345", "456"}));
}

Definition at line 37 of file csv_utility.cpp.

parse()

CSVReader csv::parse	(	csv::string_view	in,
		CSVFormat	format
	)

Shorthand function for parsing an in-memory CSV string.

Returns

A collection of CSVRow objects

Example

TEST_CASE( "Test Escaped Quote", "[read_csv_quote]" ) {
    // Per RFC 1480, escaped quotes should be doubled up
    auto csv_string = GENERATE(as<std::string> {}, 
        (
            "A,B,C\r\n" // Header row
            "123,\"234\"\"345\",456\r\n"
            "123,\"234\"345\",456\r\n"  // Unescaped single quote (not strictly valid)
            "123,\"234\"345\",\"456\"" // Quoted field at the end
        ),
        (
            "\"A\",\"B\",\"C\"\r\n" // Header row
            "123,\"234\"\"345\",456\r\n"
            "123,\"234\"345\",456\r\n" // Unescaped single quote (not strictly valid)
            "123,\"234\"345\",\"456\"" // Quoted field at the end
        )
    );
    
    SECTION("Escaped Quote") {
        auto rows = parse(csv_string);
 
        REQUIRE(rows.get_col_names() == vector<string>({ "A", "B", "C" }));
 
        // Expected Results: Double " is an escape for a single "
        vector<string> correct_row = { "123", "234\"345", "456" };
        for (auto& row : rows) {
            REQUIRE(vector<string>(row) == correct_row);
        }
    }
}

Definition at line 14 of file csv_utility.cpp.

parse_no_header()

CSVReader csv::parse_no_header

(

csv::string_view

in

)

Parses a CSV string with no headers.

Returns

A collection of CSVRow objects

Definition at line 23 of file csv_utility.cpp.