README
¶
csvdict
Golang short library that extends encoding/csv to handle importing CSV content with headers as a dictionary (map)
Usage
NewDictReader takes an argument of an io.Reader object and returns a pointer to a DictReader object that contains both a CSV Reader and a separate slice with the first line of the CSV file, assumed to be the header row.
Similarly, NewDictWriter takes two arguments, an io.Writer and a slice of headers, returning a pointer to a DictWriter object (and an error value, hopefully nil), a CSV Writer that will write the value corresponding to each header in the slice to file, in order:
dictReader, err := csvdict.NewDictReader(ioReader)
dictWriter := csvdict.NewDictWriter(ioWriter, headerSlice)
To read a line, use Read(), which returns a map with the header row contents as the indices and the contents of the row being read as the value. For example:
rowMap, err := dictReader.Read()
Optionally, to read all the contents, you can use ReadAll():
records, err := r.ReadAll()
To write to file, first write the header row line to file:
dictWriter.WriteHeaders()
Then to write records one line at a time, use Write(csvMap), which takes as an argument a map with indices matching the headers of the CSV file to be written:
err = dictWriter.Write(csvMap)
f writing line by line, to ensure that everything has been written to file before the end of execution, call Flush():
dictWriter.Flush()
Optionally, you can use WriteAll(csvMapSlice), which takes a slice of CSV maps, and calls Flush() automatically:
dictWriter.Writeall(csvMapSlice)
Documentation
¶
Overview ¶
Package csvdict is a Short Go library that extends encoding/csv to handle importing CSV content with headers as a map (dictionary)
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type DictReader ¶
type DictReader struct {
// contains filtered or unexported fields
}
DictReader contains a reference to a CSV reader and a header row slice, used to map each CSV row to its headers
Example ¶
package main
import (
"fmt"
"io"
"log"
"strings"
"github.com/kurankat/csvdict"
)
func main() {
in := `name, age, occupation
"Mark Smith",33,"Jack of all trades"
"Douglas Adams",42,Writer
Methuselah,969,Patriarch
`
r, err := csvdict.NewDictReader(strings.NewReader(in))
if err != nil {
panic(err)
}
headers := r.GetHeaderRow()
for {
record, err := r.Read()
if err == io.EOF {
break
}
if err != nil {
log.Fatal(err)
}
fmt.Printf("%v:%v %v:%v %v:%v\n", headers[0], record[headers[0]],
headers[1], record[headers[1]],
headers[2], record[headers[2]])
}
}
Output: name:Mark Smith age:33 occupation:Jack of all trades name:Douglas Adams age:42 occupation:Writer name:Methuselah age:969 occupation:Patriarch
func NewDictReader ¶
func NewDictReader(r io.Reader) (dr *DictReader, err error)
NewDictReader takes an io.Reader as an argument and returns a reference to a DictReader
func (*DictReader) GetHeaderRow ¶
func (d *DictReader) GetHeaderRow() (header []string)
GetHeaderRow returns the header row of the DictReader object
func (*DictReader) Read ¶
func (d *DictReader) Read() (csvMap map[string]string, err error)
Read reads a single line of a CSV file and returns a map where each field is mapped to its header
func (*DictReader) ReadAll ¶
func (d *DictReader) ReadAll() (records []map[string]string, err error)
ReadAll reads all the remaining records from r. Each record is a map 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 ¶
package main
import (
"fmt"
"log"
"strings"
"github.com/kurankat/csvdict"
)
func main() {
in := `name, age, occupation
"Mark Smith",33,"Jack of all trades"
"Douglas Adams",42,Writer
Methuselah,969,Patriarch
`
r, err := csvdict.NewDictReader(strings.NewReader(in))
if err != nil {
panic(err)
}
records, err := r.ReadAll()
if err != nil {
log.Fatal(err)
}
headers := r.GetHeaderRow()
for _, record := range records {
fmt.Printf("%v:%v %v:%v %v:%v\n", headers[0], record[headers[0]],
headers[1], record[headers[1]],
headers[2], record[headers[2]])
}
}
Output: name:Mark Smith age:33 occupation:Jack of all trades name:Douglas Adams age:42 occupation:Writer name:Methuselah age:969 occupation:Patriarch
type DictWriter ¶
type DictWriter struct {
// contains filtered or unexported fields
}
DictWriter contains a reference to a CSV Writer object and a header row slice
Example ¶
package main
import (
"os"
"github.com/kurankat/csvdict"
)
func main() {
headers := []string{"name", "age", "occupation"}
records := []map[string]string{
{"name": "Mark Smith", "age": "33", "occupation": "Jack of all trades"},
{"name": "Douglas Adams", "age": "42", "occupation": "Writer"},
{"name": "Methuselah", "age": "969", "occupation": "Patriarch"},
}
w := csvdict.NewDictWriter(os.Stdout, headers)
w.WriteHeaders()
for _, record := range records {
err := w.Write(record)
if err != nil {
panic(err)
}
}
w.Flush()
}
Output: name,age,occupation Mark Smith,33,Jack of all trades Douglas Adams,42,Writer Methuselah,969,Patriarch
func NewDictWriter ¶
func NewDictWriter(w io.Writer, h []string) *DictWriter
NewDictWriter takes an io.Writer and a slice containing the header row as arguments and returns a reference to a DictWriter
func (*DictWriter) Flush ¶
func (w *DictWriter) Flush()
Flush ensures that the writer is flushed to file
func (*DictWriter) Write ¶
func (w *DictWriter) Write(csvMap map[string]string) error
Write takes a map with headers as indices and field contents as values, and writes it to file as CSV
func (*DictWriter) WriteAll ¶
func (w *DictWriter) WriteAll(records []map[string]string) error
WriteAll writes multiple CSV records to w using Write and then calls Flush.
Example ¶
package main
import (
"os"
"github.com/kurankat/csvdict"
)
func main() {
headers := []string{"name", "age", "occupation"}
records := []map[string]string{
{"name": "Mark Smith", "age": "33", "occupation": "Jack of all trades"},
{"name": "Douglas Adams", "age": "42", "occupation": "Writer"},
{"name": "Methuselah", "age": "969", "occupation": "Patriarch"},
}
w := csvdict.NewDictWriter(os.Stdout, headers)
err := w.WriteAll(records)
if err != nil {
panic(err)
}
}
Output: name,age,occupation Mark Smith,33,Jack of all trades Douglas Adams,42,Writer Methuselah,969,Patriarch
func (*DictWriter) WriteHeaders ¶
func (w *DictWriter) WriteHeaders()
WriteHeaders writes the header row to file
Source Files