# Getting Started with Spreadsheet
This guide is meant to get you started using Spreadsheet. By the end of it,
you should be able to read and write Spreadsheets.

Before you can do anything, you first need to make sure all that code is
loaded:

```ruby
require 'spreadsheet'
```

## Reading is easy!

Worksheets come in various encodings. You need to tell Spreadsheet which
encoding you want to deal with. The default is UTF-8

```ruby
Spreadsheet.client_encoding = 'UTF-8'
```

Let's open a workbook:

```ruby
book = Spreadsheet.open '/path/to/an/excel-file.xls'
```

We can either access all the worksheets in a workbook...

```ruby
book.worksheets
```

...or access them by index or name (encoded in your `client_encoding`).

```ruby
sheet1 = book.worksheet 0
sheet2 = book.worksheet 'Sheet1'
```

Now you can either iterate over all rows that contain some data. A call to
`Worksheet.each` without arguments will omit empty rows at the beginning of the
worksheet:

```ruby
sheet1.each do |row|
  # do something interesting with a row
end
```

Or you can tell a worksheet how many rows should be omitted at the beginning.
The following starts at the 3rd row, regardless of whether or not it or the
preceding rows contain any data:

```ruby
sheet2.each 2 do |row|
  # do something interesting with a row
end
```

Or you can access rows directly, by their index (0-based):

```ruby
row = sheet1.row(3)
```

To access the values stored in a row, treat the row like an array.

```ruby
row[0]
```

This will return a `String`, a `Float`, an `Integer`, a `Formula`, a `Link` or a `Date`
or `DateTime` object - or `nil` if the cell is empty.

More information about the formatting of a cell can be found in the format
with the equivalent index:

```ruby
row.format 2
```

## Writing is easy
As before, make sure you have Spreadsheet required and the client_encoding
set. Then make a new Workbook:

```ruby
book = Spreadsheet::Workbook.new
```

Add a Worksheet and you're good to go:

```ruby
sheet1 = book.create_worksheet
```

This will create a Worksheet with the Name "Worksheet1". If you prefer another
name, you may do either of the following:

```ruby
sheet2 = book.create_worksheet :name => 'My Second Worksheet'
sheet1.name = 'My First Worksheet'
```

Now, add data to the Worksheet, using either Worksheet#[]=,
Worksheet#update_row, or work directly on Row using any of the Array-Methods
that modify an Array in place:

```ruby
sheet1.row(0).concat %w{Name Country Acknowlegement}
sheet1[1,0] = 'Japan'
row = sheet1.row(1)
row.push 'Creator of Ruby'
row.unshift 'Yukihiro Matsumoto'
sheet1.row(2).replace [ 'Daniel J. Berger', 'U.S.A.',
                        'Author of original code for Spreadsheet::Excel' ]
sheet1.row(3).push 'Charles Lowe', 'Author of the ruby-ole Library'
sheet1.row(3).insert 1, 'Unknown'
sheet1.update_row 4, 'Hannes Wyss', 'Switzerland', 'Author'
```

Add some Formatting for flavour:

```ruby
sheet1.row(0).height = 18

format = Spreadsheet::Format.new :color => :blue,
                                 :weight => :bold,
                                 :size => 18
sheet1.row(0).default_format = format

bold = Spreadsheet::Format.new :weight => :bold
4.times do |x| sheet1.row(x + 1).set_format(0, bold) end
```

And finally, write the Excel File:

```ruby
book.write '/path/to/output/excel-file.xls'
```

## Modifying an existing Document

Spreadsheet has some limited support for modifying an existing Document. This
is done by copying verbatim those parts of an Excel-document which Spreadsheet
can't modify (yet), recalculating relevant offsets, and writing the data that
can be changed.
Here's what should work:

* Adding, changing and deleting cells.
* You should be able to fill in Data to be evaluated by predefined Formulas

Limitations:

* Spreadsheet can only write BIFF8 (Excel97 and higher). The results of
modifying an earlier version of Excel are undefined.
* Spreadsheet does not modify Formatting at present. That means in particular
that if you set the Value of a Cell to a Date, it can only be read as a
Date if its Format was set correctly prior to the change.
* Although it is theoretically possible, it is not recommended to write the
resulting Document back to the same File/IO that it was read from.

And here's how it works:

```ruby
book = Spreadsheet.open '/path/to/an/excel-file.xls'
sheet = book.worksheet 0
sheet.each do |row|
  row[0] *= 2
end
book.write '/path/to/output/excel-file.xls'
```

Or you can directly access the cell that you want and add your text on it:

```ruby
sheet.rows[2][1] = "X"
```

## Date and DateTime
Excel does not know a separate Datatype for Dates. Instead it encodes Dates
into standard floating-point numbers and recognizes a Date-Cell by its
formatting-string:

```ruby
row.format(3).number_format
```

Whenever a Cell's Format describes a Date or Time, Spreadsheet will give you
the decoded Date or DateTime value. Should you need to access the underlying
Float, you may do the following:

```ruby
row.at(3)
```

If for some reason the Date-recognition fails, you may force Date-decoding:

```ruby
row.date(3)
row.datetime(3)
```

When you set the value of a Cell to a Date, Time or DateTime, Spreadsheet will
try to set the cell's number-format to a corresponding value (one of Excel's
builtin formats). If you have already defined a Date- or DateTime-format,
Spreadsheet will use that instead. If a format has already been applied to
a particular Cell, Spreadsheet will leave it untouched:

```ruby
row[4] = Date.new 1975, 8, 21
# -> assigns the builtin Date-Format: 'M/D/YY'
book.add_format Format.new(:number_format => 'DD.MM.YYYY hh:mm:ss')
row[5] = DateTime.new 2008, 10, 12, 11, 59
# -> assigns the added DateTime-Format: 'DD.MM.YYYY hh:mm:ss'
row.set_format 6, Format.new(:number_format => 'D-MMM-YYYY')
row[6] = Time.new 2008, 10, 12
# -> the Format of cell 6 is left unchanged.
```

## Outline (Grouping) and Hiding
Spreadsheet supports outline (grouping) and hiding functions from version 
0.6.5. In order to hide rows or columns, you can use 'hidden' property. 
As for outline, 'outline_level' property is also available. You can use 
both 'hidden' and 'outline_level' at the same time.

You can create a new file with outline and hiding rows and columns as
follows:

```ruby
require 'spreadsheet'

# create a new book and sheet
book = Spreadsheet::Workbook.new
sheet = book.create_worksheet
5.times {|j| 5.times {|i| sheet[j,i] = (i+1)*10**j}}

# column
sheet.column(2).hidden = true
sheet.column(3).hidden = true
sheet.column(2).outline_level = 1
sheet.column(3).outline_level = 1

# row
sheet.row(2).hidden = true
sheet.row(3).hidden = true
sheet.row(2).outline_level = 1
sheet.row(3).outline_level = 1

# save file
book.write 'out.xls'
```

Also you can read an existing file and change the hidden and outline
properties. Here is the example below:

```ruby
require 'spreadsheet'

# read an existing file
file = ARGV[0]
book = Spreadsheet.open(file, 'rb')
sheet= book.worksheet(0)

# column
sheet.column(2).hidden = true
sheet.column(3).hidden = true
sheet.column(2).outline_level = 1
sheet.column(3).outline_level = 1

# row
sheet.row(2).hidden = true
sheet.row(3).hidden = true
sheet.row(2).outline_level = 1
sheet.row(3).outline_level = 1

# save file
book.write "out.xls"
```

Notes
* The outline_level should be under 8, which is due to the Excel data format.

## Allow access to rendered output instead of just writing a file

```ruby
file_contents = StringIO.new
book.write file_contents # => Now file_contents contains the rendered file output
```

Also see: https://github.com/zdavatz/spreadsheet/issues/125#issuecomment-75541041

## More about Encodings
Spreadsheet assumes it's running on Ruby 1.8 with Iconv-support. It is your
responsibility to handle Conversion Errors, or to prevent them e.g. by using
the Iconv Transliteration and Ignore flags:
Spreadsheet.client_encoding = 'LATIN1//TRANSLIT//IGNORE'

## Page setup (for printing)

```ruby
sheet.pagesetup[:orientation] = :landscape # or :portrait (default)
sheet.pagesetup[:adjust_to] = 85 # default 100
```

## Backward Compatibility
Spreadsheet is designed to be a drop-in replacement for both ParseExcel and
Spreadsheet::Excel. It provides a number of require-paths for backward
compatibility with its predecessors. If you have been working with ParseExcel,
you have probably used one or more of the following:

```ruby
require 'parseexcel'
require 'parseexcel/parseexcel'
require 'parseexcel/parser'
```

Either of the above will define the ParseExcel.parse method as a facade to
Spreadsheet.open. Additionally, this will alter Spreadsheets behavior to define
the ParseExcel::Worksheet::Cell class and fill each parsed Row with instances
thereof, which in turn provide ParseExcel's Cell#to_s(encoding) and Cell#date
methods.
You will have to manually uninstall the parseexcel library.

If you are upgrading from Spreadsheet::Excel, you were probably using
Workbook#add_worksheet and Worksheet#write, write_row or write_column.
Use the following to load the code which provides them:

```ruby
require 'spreadsheet/excel'
```

Again, you will have to manually uninstall the spreadsheet-excel library.

If you perform fancy formatting, you may run into trouble as the
Format implementation has changed considerably. If that is the case, please
drop me a line at "zdavatz at ywesee dot com" and I will try to help you. Don't
forget to include the offending code-snippet!

All compatibility code is deprecated and will be removed in version 1.0.0

## Cautionary note about cell content length
For offline versions of Excel there is a limitation on the maximum length of
the contents that can be written to a single cell of 32KB. Spreadsheet will
allow you to exceed that limit, however Excel will interpret this as file
corruption.

Other spreadsheet authoring tools (Office 365, LibreOffice) are able to open
files exceeding this limit, however saving the file in those tools will likely
result in cell content being truncated back to 32KB.