Package tech.tablesaw.io.csv

Class CsvReader

java.lang.Object

tech.tablesaw.io.FileReader

tech.tablesaw.io.csv.CsvReader

All Implemented Interfaces:

DataReader<CsvReadOptions>

@Immutable
public class CsvReader
extends FileReader
implements DataReader<CsvReadOptions>

Constructor Summary

Constructors

Constructor	Description
CsvReader()	Constructs a CsvReader

Method Summary

Modifier and Type	Method	Description
protected ColumnType[]	detectColumnTypes(Reader reader, CsvReadOptions options)	Estimates and returns the type for each column in the delimited text file file
String	printColumnTypes(CsvReadOptions options)	Returns a string representation of the column types in file csvFilename, as determined by the type-detection algorithm
Table	read(CsvReadOptions options)
Table	read(Source source)
static void	register(ReaderRegistry registry)

Methods inherited from class tech.tablesaw.io.FileReader

getColumnNames, getColumnTypes, getColumnTypes, getTypeString, parseRows, parseRows

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CsvReader

public CsvReader()

Constructs a CsvReader

Method Detail

register

public static void register(ReaderRegistry registry)

read

public Table read(CsvReadOptions options)

Specified by:

read in interface DataReader<CsvReadOptions>

printColumnTypes

public String printColumnTypes(CsvReadOptions options)
                        throws IOException

Returns a string representation of the column types in file csvFilename, as determined by the type-detection algorithm

This method is intended to help analysts quickly fix any erroneous types, by printing out the types in a format such that they can be edited to correct any mistakes, and used in an array literal

For example:

LOCAL_DATE, // 0 date SHORT, // 1 approval STRING, // 2 who

Note that the types are array separated, and that the index position and the column name are printed such that they would be interpreted as comments if you paste the output into an array:

Throws:

IOException - if file cannot be read

detectColumnTypes

protected ColumnType[] detectColumnTypes(Reader reader,
                                         CsvReadOptions options)

Estimates and returns the type for each column in the delimited text file file

The type is determined by checking a sample of the data in the file. Because only a sample of the data is checked, the types may be incorrect. If that is the case a Parse Exception will be thrown.

The method printColumnTypes() can be used to print a list of the detected columns that can be corrected and used to explicitly specify the correct column types.

read

public Table read(Source source)

Specified by:

read in interface DataReader<CsvReadOptions>