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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.mdReading Files](./reading-files.md](./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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