These are the errors that can be returned in [ParseError.Err].
var (
ErrBareQuote = errors.New("bare \" in non-quoted-field")
ErrQuote = errors.New("extraneous or missing \" in quoted-field")
ErrFieldCount = errors.New("wrong number of fields")
// Deprecated: ErrTrailingComma is no longer used.
ErrTrailingComma = errors.New("extra delimiter at end of line")
)
A ParseError is returned for parsing errors. Line and column numbers are 1-indexed.
type ParseError struct {
StartLine int // Line where the record starts; added in Go 1.10
Line int // Line where the error occurred
Column int // Column (1-based byte index) where the error occurred
Err error // The actual error
}
func (e *ParseError) Error() string
func (e *ParseError) Unwrap() error
A Reader reads records from a CSV-encoded file.
As returned by NewReader, a Reader expects input conforming to RFC 4180. The exported fields can be changed to customize the details before the first call to Reader.Read or Reader.ReadAll.
The Reader converts all \r\n sequences in its input to plain \n, including in multiline field values, so that the returned data does not depend on which line-ending convention an input file uses.
type Reader struct {
// Comma is the field delimiter.
// It is set to comma (',') by NewReader.
// Comma must be a valid rune and must not be \r, \n,
// or the Unicode replacement character (0xFFFD).
Comma rune
// Comment, if not 0, is the comment character. Lines beginning with the
// Comment character without preceding whitespace are ignored.
// With leading whitespace the Comment character becomes part of the
// field, even if TrimLeadingSpace is true.
// Comment must be a valid rune and must not be \r, \n,
// or the Unicode replacement character (0xFFFD).
// It must also not be equal to Comma.
Comment rune
// FieldsPerRecord is the number of expected fields per record.
// If FieldsPerRecord is positive, Read requires each record to
// have the given number of fields. If FieldsPerRecord is 0, Read sets it to
// the number of fields in the first record, so that future records must
// have the same field count. If FieldsPerRecord is negative, no check is
// made and records may have a variable number of fields.
FieldsPerRecord int
// If LazyQuotes is true, a quote may appear in an unquoted field and a
// non-doubled quote may appear in a quoted field.
LazyQuotes bool
// If TrimLeadingSpace is true, leading white space in a field is ignored.
// This is done even if the field delimiter, Comma, is white space.
TrimLeadingSpace bool
// ReuseRecord controls whether calls to Read may return a slice sharing
// the backing array of the previous call's returned slice for performance.
// By default, each call to Read returns newly allocated memory owned by the caller.
ReuseRecord bool // Go 1.9
// Deprecated: TrailingComma is no longer used.
TrailingComma bool
// contains filtered or unexported fields
}
▹ Example
▹ Example (Options)
func NewReader(r io.Reader) *Reader
NewReader returns a new Reader that reads from r.
func (r *Reader) FieldPos(field int) (line, column int)
FieldPos returns the line and column corresponding to the start of the field with the given index in the slice most recently returned by Reader.Read. Numbering of lines and columns starts at 1; columns are counted in bytes, not runes.
If this is called with an out-of-bounds index, it panics.
func (r *Reader) InputOffset() int64
InputOffset returns the input stream byte offset of the current reader position. The offset gives the location of the end of the most recently read row and the beginning of the next row.
func (r *Reader) Read() (record []string, err error)
Read reads one record (a slice of fields) from r. If the record has an unexpected number of fields, Read returns the record along with the error ErrFieldCount. If the record contains a field that cannot be parsed, Read returns a partial record along with the parse error. The partial record contains all fields read before the error. If there is no data left to be read, Read returns nil, io.EOF. If [Reader.ReuseRecord] is true, the returned slice may be shared between multiple calls to Read.
func (r *Reader) ReadAll() (records [][]string, err error)
ReadAll reads all the remaining records from r. Each record is a slice of fields. A successful call returns err == nil, not err == io.EOF. Because ReadAll is defined to read until EOF, it does not treat end of file as an error to be reported.
▹ Example
A Writer writes records using CSV encoding.
As returned by NewWriter, a Writer writes records terminated by a newline and uses ',' as the field delimiter. The exported fields can be changed to customize the details before the first call to Writer.Write or Writer.WriteAll.
[Writer.Comma] is the field delimiter.
If [Writer.UseCRLF] is true, the Writer ends each output line with \r\n instead of \n.
The writes of individual records are buffered. After all data has been written, the client should call the Writer.Flush method to guarantee all data has been forwarded to the underlying io.Writer. Any errors that occurred should be checked by calling the Writer.Error method.
type Writer struct {
Comma rune // Field delimiter (set to ',' by NewWriter)
UseCRLF bool // True to use \r\n as the line terminator
// contains filtered or unexported fields
}
▹ Example
func NewWriter(w io.Writer) *Writer
NewWriter returns a new Writer that writes to w.
func (w *Writer) Error() error
Error reports any error that has occurred during a previous Writer.Write or Writer.Flush.
func (w *Writer) Flush()
Flush writes any buffered data to the underlying io.Writer. To check if an error occurred during Flush, call Writer.Error.
func (w *Writer) Write(record []string) error
Write writes a single CSV record to w along with any necessary quoting. A record is a slice of strings with each string being one field. Writes are buffered, so Writer.Flush must eventually be called to ensure that the record is written to the underlying io.Writer.
func (w *Writer) WriteAll(records [][]string) error
WriteAll writes multiple CSV records to w using Writer.Write and then calls Writer.Flush, returning any error from the Flush.
▹ Example