Class CSV
Handles CSV file.
Summary
| Return type | Function and summary |
|---|---|
| CSV | new(string fileName, string rw, int encoding, int lineBreak) Create a CSV object, open the file. |
| bool | canRead() Is it possible to read? |
| bool | canWrite() Is it possible to write? |
| close() Close the file | |
| Map | readLine() Read a line and return a map of column name (header) to value, nil if end of file is reached. |
| Map | select(string idField, function filterFunction) Read the whole CSV file, filter results and return a Map idField -> line (line is a Map column->value) |
| writeHeader(string columnName) In Write mode, add header if no data were already written | |
| writeLine(data) Writes a line of data. |
Methods
CSV:new(string fileName, string rw, int encoding, int lineBreak)
Create a CSV object, open the file.
As the file is opened, you must call :close() method once reading/writing is finished.
| Parameter | Type | Default | Description |
|---|---|---|---|
| fileName | string | The CSV file that will be read or written | |
| rw | string | "r" for read, "w" for write access. | |
| encoding | int | UTF8_STR_ENCODING | Character encoding |
| lineBreak | int | UNKNOWN_CR for read, WIN_CR for write | Line break |
- Return
- CSV: The CSV object
- Error
- if file open fails
CSV:close()
Close the file
CSV:canRead()
Is it possible to read?
- Return
- bool:
trueif file is not closed and was open in read mode.
CSV:canWrite()
Is it possible to write?
- Return
- bool:
trueif file is not closed and was open in write mode.
CSV:writeHeader(string columnName)
In Write mode, add header if no data were already written
| Parameter | Type | Default | Description |
|---|---|---|---|
| columnName | string | Column name |
- Errors
- if file is closed or was not opened in write mode
- if datas was already added
- if columnName is empty or nil or already exists
CSV:writeLine(data)
Writes a line of data.
If data is a table or a Collection, it's iterated untile the number of header is reached.
If Map, datas are picked in Map according to header order.
In all cases, missing data are inserted as empty strings
| Parameter | Type | Default | Description |
|---|---|---|---|
| data | A table, Collection or Map |
- Errors
- if file is closed or was not opened in write mode
- if no header was written before
- if data is nil or unrecognized type.
CSV:readLine()
Read a line and return a map of column name (header) to value, nil if end of file is reached.
- Return
- Map: The line of data in Map columnName->value, or nil if end of file is reached.
CSV:select(string idField, function filterFunction)
Read the whole CSV file, filter results and return a Map idField -> line (line is a Map column->value)
| Parameter | Type | Default | Description |
|---|---|---|---|
| idField | string | # | One of column used as key, or # for the row number |
| filterFunction | function | nil | A function receiving each line (as a Map), returing true to include, false to exclude in results. |
- Return
- Map: Key sorting is not guaranteed