Basic operation
Main article: Spreadsheet
Microsoft Excel has the basic features of all spreadsheets,[4] using a grid of cells arranged in numbered rows and letter-named columns to organize data manipulations like arithmetic operations. It has a battery of supplied functions to answer statistical, engineering and financial needs. In addition, it can display data as line graphs, histograms and charts, and with a very limited three-dimensional graphical display. It allows sectioning of data to view its dependencies on various factors for different perspectives (using pivot tables and the scenario manager).[5] It has a programming aspect, Visual Basic for Applications, allowing the user to employ a wide variety of numerical methods, for example, for solving differential equations of mathematical physics,[6][7] and then reporting the results back to the spreadsheet. It also has a variety of interactive features allowing user interfaces that can completely hide the spreadsheet from the user, so the spreadsheet presents itself as a so-called application, or decision support system (DSS), via a custom-designed user interface, for example, a stock analyzer,[8] or in general, as a design tool that asks the user questions and provides answers and reports.[9][10][11] In a more elaborate realization, an Excel application can automatically poll external databases and measuring instruments using an update schedule,[12] analyze the results, make a Wordreport or PowerPoint slide show, and e-mail these presentations on a regular basis to a list of participants.
Microsoft allows for a number of optional command-line switches to control the manner in which Excel starts.[13]
Macro programming
VBA programming
Main article: Visual Basic for Applications
The Windows version of Excel supports programming through Microsoft's Visual Basic for Applications (VBA), which is a dialect of Visual Basic. Programming with VBA allows spreadsheet manipulation that is awkward or impossible with standard spreadsheet techniques. Programmers may write code directly using the Visual Basic Editor (VBE), which includes a window for writing code, debugging code, and code module organization environment. The user can implement numerical methods as well as automating tasks such as formatting or data organization in VBA[14] and guide the calculation using any desired intermediate results reported back to the spreadsheet.
VBA was removed from Mac Excel 2008, as the developers did not believe that a timely release would allow porting the VBA engine natively to Mac OS X. VBA was restored in the next version, Mac Excel 2011,[15] although the build lacks support forActiveX objects, impacting some high level developer tools.[16]
A common and easy way to generate VBA code is by using the Macro Recorder.[17] The Macro Recorder records actions of the user and generates VBA code in the form of a macro. These actions can then be repeated automatically by running the macro. The macros can also be linked to different trigger types like keyboard shortcuts, a command button or a graphic. The actions in the macro can be executed from these trigger types or from the generic toolbar options. The VBA code of the macro can also be edited in the VBE. Certain features such as loop functions and screen prompts by their own properties, and some graphical display items, cannot be recorded, but must be entered into the VBA module directly by the programmer. Advanced users can employ user prompts to create an interactive program, or react to events such as sheets being loaded or changed.
Macro Recorded code may not be compatible between Excel versions. Some code that is used in Excel 2010 can not be used in Excel 2003. Making a Macro that changes the cell colors and making changes to other aspects of cells may not be backward compatible.
VBA code interacts with the spreadsheet through the Excel Object Model,[18] a vocabulary identifying spreadsheet objects, and a set of supplied functions or methods that enable reading and writing to the spreadsheet and interaction with its users (for example, through custom toolbars or command bars and message boxes). User-created VBA subroutines execute these actions and operate like macros generated using the macro recorder, but are more flexible and efficient.
History
From its first version Excel supported end user programming of macros (automation of repetitive tasks) and user defined functions (extension of Excel's built-in function library). In early versions of Excel these programs were written in a macro language whose statements had formula syntax and resided in the cells of special purpose macro sheets (stored with file extension .XLM in Windows.) XLM was the default macro language for Excel through Excel 4.0.[19] Beginning with version 5.0 Excel recorded macros in VBA by default but with version 5.0 XLM recording was still allowed as an option. After version 5.0 that option was discontinued. All versions of Excel, including Excel 2010 are capable of running an XLM macro, though Microsoft discourages their use.[20]
Charts
Excel supports charts, graphs, or histograms generated from specified groups of cells. The generated graphic component can either be embedded within the current sheet, or added as a separate object.
These displays are dynamically updated if the content of cells change. For example, suppose that the important design requirements are displayed visually; then, in response to a user's change in trial values for parameters, the curves describing the design change shape, and their points of intersection shift, assisting the selection of the best design.
Data storage and communication
Number of rows and columns
Versions of Excel up to 7.0 had a limitation in the size of their data sets of 16K (214 = 16384) rows. Versions 8.0 through 11.0 could handle 64K (216 = 65536) rows and 256 columns (28 as label 'IV'). Version 12.0 can handle 1M (220 = 1048576) rows, and 16384 (214 as label 'XFD') columns.[21]
File formats
| Filename extension | .xls, (.xlsx, .xlsm, .xlsb - Excel 2007) |
|---|---|
| Internet media type | application/vnd.ms-excel |
| Uniform Type Identifier (UTI) | com.microsoft.excel.xls[22] |
| Developed by | Microsoft |
| Type of format | Spreadsheet |
Microsoft Excel up until 2007 version used a proprietary binary file format called Excel Binary File Format (.XLS) as its primary format.[23] Excel 2007 uses Office Open XML as its primary file format, an XML-based format that followed after a previous XML-based format called "XML Spreadsheet" ("XMLSS"), first introduced in Excel 2002.[24]
Although supporting and encouraging the use of new XML-based formats as replacements, Excel 2007 remained backwards-compatible with the traditional, binary formats. In addition, most versions of Microsoft Excel can read CSV, DBF, SYLK, DIF, and other legacy formats. Support for some older file formats was removed in Excel 2007.[25] The file formats were mainly from DOS-based programs.
Binary
OpenOffice.org has created documentation of the Excel format.[26] Since then Microsoft made the Excel binary format specification available to freely download.[27]
XML Spreadsheet
Main article: Microsoft Office XML formats
The XML Spreadsheet format introduced in Excel 2002[24] is a simple, XML based format missing some more advanced features like storage of VBA macros. Though the intended file extension for this format is .xml, the program also correctly handles XML files with .xls extension. This feature is widely used by third-party applications (e.g. MySQLQuery Browser) to offer "export to Excel" capabilities without implementing binary file format. The following example will be correctly opened by Excel if saved either as Book1.xmlor Book1.xls: