# PHPExcel User Documentation – Reading Spreadsheet Files
## Spreadsheet Reader Options
Once you have created a reader object for the workbook that you want to load, you have the opportunity to set additional options before executing the load() method.
### Reading Only Data from a Spreadsheet File
If you're only interested in the cell values in a workbook, but don't need any of the cell formatting information, then you can set the reader to read only the data values and any formulae from each cell using the setReadDataOnly() method.
/** Advise the Reader that we only want to load cell data **/
$objReader->setReadDataOnly(true);
/** Load $inputFileName to a PHPExcel Object **/
$objPHPExcel = $objReader->load($inputFileName);
```
> See Examples/Reader/exampleReader05.php for a working example of this code.
It is important to note that Workbooks (and PHPExcel) store dates and times as simple numeric values: they can only be distinguished from other numeric values by the format mask that is applied to that cell. When setting read data only to true, PHPExcel doesn't read the cell format masks, so it is not possible to differentiate between dates/times and numbers.
The Gnumeric loader has been written to read the format masks for date values even when read data only has been set to true, so it can differentiate between dates/times and numbers; but this change hasn't yet been implemented for the other readers.
Reading Only Data from a Spreadsheet File applies to Readers:
If your workbook contains a number of worksheets, but you are only interested in reading some of those, then you can use the setLoadSheetsOnly() method to identify those sheets you are interested in reading.
To read a single sheet, you can pass that sheet name as a parameter to the setLoadSheetsOnly() method.
### Reading Only Specific Columns and Rows from a File (Read Filters)
If you are only interested in reading part of a worksheet, then you can write a filter class that identifies whether or not individual cells should be read by the loader. A read filter must implement the PHPExcel_Reader_IReadFilter interface, and contain a readCell() method that accepts arguments of $column, $row and $worksheetName, and return a boolean true or false that indicates whether a workbook cell identified by those arguments should be read or not.
> See Examples/Reader/exampleReader09.php for a working example of this code.
This example is not particularly useful, because it can only be used in a very specific circumstance (when you only want cells in the range A1:E7 from your worksheet. A generic Read Filter would probably be more useful:
$filterSubset = new MyReadFilter(9,15,range('G','K'));
```
> See Examples/Reader/exampleReader10.php for a working example of this code.
This can be particularly useful for conserving memory, by allowing you to read and process a large workbook in “chunks”: an example of this usage might be when transferring data from an Excel worksheet to a database.
### Combining Multiple Files into a Single PHPExcel Object
While you can limit the number of worksheets that are read from a workbook file using the setLoadSheetsOnly() method, certain readers also allow you to combine several individual "sheets" from different files into a single PHPExcel object, where each individual file is a single worksheet within that workbook. For each file that you read, you need to indicate which worksheet index it should be loaded into using the setSheetIndex() method of the $objReader, then use the loadIntoExisting() method rather than the load() method to actually read the file into that worksheet.
> See Examples/Reader/exampleReader13.php for a working example of this code.
Note that using the same sheet index for multiple sheets won't append files into the same sheet, but overwrite the results of the previous load. You cannot load multiple CSV files into the same worksheet.
Combining Multiple Files into a Single PHPExcel Object applies to:
An Xls BIFF .xls file is limited to 65536 rows in a worksheet, while the Xlsx Microsoft Office Open XML SpreadsheetML .xlsx file is limited to 1,048,576 rows in a worksheet; but a CSV file is not limited other than by available disk space. This means that we wouldn’t ordinarily be able to read all the rows from a very large CSV file that exceeded those limits, and save it as an Xls or Xlsx file. However, by using Read Filters to read the CSV file in “chunks” (using the chunkReadFilter Class that we defined in section REF _Ref275604563 \r \p 5.3 above), and the setSheetIndex() method of the $objReader, we can split the CSV file across several individual worksheets.
> See Examples/Reader/exampleReader14.php for a working example of this code.
This code will read 65,530 rows at a time from the CSV file that we’re loading, and store each "chunk" in a new worksheet.
The setContiguous() method for the Reader is important here. It is applicable only when working with a Read Filter, and identifies whether or not the cells should be stored by their position within the CSV file, or their position relative to the filter.
For example, if the filter returned true for cells in the range B2:C3, then with setContiguous set to false (the default) these would be loaded as B2:C3 in the PHPExcel object; but with setContiguous set to true, they would be loaded as A1:B2.
Splitting a single loaded file across multiple worksheets applies to:
The CSV loader defaults to loading a file where comma is used as the separator, but you can modify this to load tab- or pipe-separated value files using the setDelimiter() method.
When loading data from a file that contains no formatting information, such as a CSV file, then data is read either as strings or numbers (float or integer). This means that PHPExcel does not automatically recognise dates/times (such as "16-Apr-2009" or "13:30"), booleans ("TRUE" or "FALSE"), percentages ("75%"), hyperlinks ("http://www.phpexcel.net"), etc as anything other than simple strings. However, you can apply additional processing that is executed against these values during the load process within a Value Binder.
A Value Binder is a class that implement the PHPExcel_Cell_IValueBinder interface. It must contain a bindValue() method that accepts a PHPExcel_Cell and a value as arguments, and return a boolean true or false that indicates whether the workbook cell has been populated with the value or not. The Advanced Value Binder implements such a class: amongst other tests, it identifies a string comprising "TRUE" or "FALSE" (based on locale settings) and sets it to a boolean; or a number in scientific format (e.g. "1.234e-5") and converts it to a float; or dates and times, converting them to their Excel timestamp value – before storing the value in the cell object. It also sets formatting for strings that are identified as dates, times or percentages. It could easily be extended to provide additional handling (including text or cell formatting) when it encountered a hyperlink, or HTML markup within a CSV file.
So using a Value Binder allows a great deal more flexibility in the loader logic when reading unformatted text files.
