60 lines
2.0 KiB
Markdown
60 lines
2.0 KiB
Markdown
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# Creating a spreadsheet
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## The `Spreadsheet` class
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The `Spreadsheet` class is the core of PhpSpreadsheet. It contains
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references to the contained worksheets, document security settings and
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document meta data.
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To simplify the PhpSpreadsheet concept: the `Spreadsheet` class
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represents your workbook.
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Typically, you will create a workbook in one of two ways, either by
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loading it from a spreadsheet file, or creating it manually. A third
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option, though less commonly used, is cloning an existing workbook that
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has been created using one of the previous two methods.
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### Loading a Workbook from a file
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Details of the different spreadsheet formats supported, and the options
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available to read them into a Spreadsheet object are described fully in
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the [Reading Files](./reading-files.md) document.
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``` php
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$inputFileName = './sampleData/example1.xls';
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/** Load $inputFileName to a Spreadsheet object **/
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$spreadsheet = \PhpOffice\PhpSpreadsheet\IOFactory::load($inputFileName);
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```
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### Creating a new workbook
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If you want to create a new workbook, rather than load one from file,
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then you simply need to instantiate it as a new Spreadsheet object.
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``` php
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/** Create a new Spreadsheet Object **/
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$spreadsheet = new \PhpOffice\PhpSpreadsheet\Spreadsheet();
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```
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A new workbook will always be created with a single worksheet.
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## Clearing a Workbook from memory
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The PhpSpreadsheet object contains cyclic references (e.g. the workbook
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is linked to the worksheets, and the worksheets are linked to their
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parent workbook) which cause problems when PHP tries to clear the
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objects from memory when they are `unset()`, or at the end of a function
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when they are in local scope. The result of this is "memory leaks",
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which can easily use a large amount of PHP's limited memory.
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This can only be resolved manually: if you need to unset a workbook,
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then you also need to "break" these cyclic references before doing so.
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PhpSpreadsheet provides the `disconnectWorksheets()` method for this
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purpose.
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``` php
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$spreadsheet->disconnectWorksheets();
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unset($spreadsheet);
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```
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