Class: FasterCSV::Row
- Inherits:
-
Object
- Object
- FasterCSV::Row
- Extends:
- Forwardable
- Includes:
- Enumerable
- Defined in:
- lib/faster_csv.rb
Overview
A FasterCSV::Row is part Array and part Hash. It retains an order for the fields and allows duplicates just as an Array would, but also allows you to access fields by name just as you could if they were in a Hash.
All rows returned by FasterCSV will be constructed from this class, if header row processing is activated.
Instance Method Summary
-
- (Object) <<(arg)
:call-seq:.
-
- (Object) ==(other)
Returns true if this row contains the same headers and fields in the same order as other.
-
- (Object) []=(*args)
:call-seq:.
-
- (Object) delete(header_or_index, minimum_index = 0)
:call-seq:.
-
- (Object) delete_if(&block)
The provided block is passed a header and field for each pair in the row and expected to return true or false, depending on whether the pair should be deleted.
-
- (Object) each(&block)
Yields each pair of the row as header and field tuples (much like iterating over a Hash).
-
- (Object) field(header_or_index, minimum_index = 0)
(also: #[])
:call-seq:.
-
- (Boolean) field?(data)
Returns true if data matches a field in this row, and false otherwise.
-
- (Boolean) field_row?
Returns true if this is a field row.
-
- (Object) fields(*headers_and_or_indices)
(also: #values_at)
This method accepts any number of arguments which can be headers, indices, Ranges of either, or two-element Arrays containing a header and offset.
-
- (Boolean) header?(name)
(also: #include?)
Returns true if name is a header for this row, and false otherwise.
-
- (Boolean) header_row?
Returns true if this is a header row.
-
- (Object) headers
Returns the headers of this row.
-
- (Object) index(header, minimum_index = 0)
:call-seq:.
-
- (Row) initialize(headers, fields, header_row = false)
constructor
Construct a new FasterCSV::Row from headers and fields, which are expected to be Arrays.
-
- (Object) inspect
A summary of fields, by header.
-
- (Object) push(*args)
A shortcut for appending multiple fields.
-
- (Object) to_csv(options = Hash.new)
(also: #to_s)
Returns the row as a CSV String.
-
- (Object) to_hash
Collapses the row into a simple Hash.
Constructor Details
- (Row) initialize(headers, fields, header_row = false)
Construct a new FasterCSV::Row from headers and fields, which are expected to be Arrays. If one Array is shorter than the other, it will be padded with nil objects.
The optional header_row parameter can be set to true to indicate, via FasterCSV::Row.header_row?() and FasterCSV::Row.field_row?(), that this is a header row. Otherwise, the row is assumes to be a field row.
A FasterCSV::Row object supports the following Array methods through delegation:
- empty?()
- length()
- size()
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# File 'lib/faster_csv.rb', line 113 def initialize(headers, fields, header_row = false) @header_row = header_row # handle extra headers or fields @row = if headers.size > fields.size headers.zip(fields) else fields.zip(headers).map { |pair| pair.reverse } end end |
Instance Method Details
- (Object) <<(arg)
:call-seq:
<<( field ) <<( header_and_field_array ) <<( header_and_field_hash )
If a two-element Array is provided, it is assumed to be a header and field and the pair is appended. A Hash works the same way with the key being the header and the value being the field. Anything else is assumed to be a lone field which is appended with a nil header.
This method returns the row for chaining.
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# File 'lib/faster_csv.rb', line 217 def <<(arg) if arg.is_a?(Array) and arg.size == 2 # appending a header and name @row << arg elsif arg.is_a?(Hash) # append header and name pairs arg.each { |pair| @row << pair } else # append field value @row << [nil, arg] end self # for chaining end |
- (Object) ==(other)
Returns true if this row contains the same headers and fields in the same order as other.
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# File 'lib/faster_csv.rb', line 352 def ==(other) @row == other.row end |
- (Object) []=(*args)
:call-seq:
[]=( header, value ) []=( header, offset, value ) []=( index, value )
Looks up the field by the semantics described in FasterCSV::Row.field() and assigns the value.
Assigning past the end of the row with an index will set all pairs between to [nil, nil]. Assigning to an unused header appends the new pair.
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# File 'lib/faster_csv.rb', line 184 def []=(*args) value = args.pop if args.first.is_a? Integer if @row[args.first].nil? # extending past the end with index @row[args.first] = [nil, value] @row.map! { |pair| pair.nil? ? [nil, nil] : pair } else # normal index assignment @row[args.first][1] = value end else index = index(*args) if index.nil? # appending a field self << [args.first, value] else # normal header assignment @row[index][1] = value end end end |
- (Object) delete(header_or_index, minimum_index = 0)
:call-seq:
delete( header ) delete( header, offset ) delete( index )
Used to remove a pair from the row by header or index. The pair is located as described in FasterCSV::Row.field(). The deleted pair is returned, or nil if a pair could not be found.
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# File 'lib/faster_csv.rb', line 252 def delete(header_or_index, minimum_index = 0) if header_or_index.is_a? Integer # by index @row.delete_at(header_or_index) else # by header @row.delete_at(index(header_or_index, minimum_index)) end end |
- (Object) delete_if(&block)
The provided block is passed a header and field for each pair in the row and expected to return true or false, depending on whether the pair should be deleted.
This method returns the row for chaining.
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# File 'lib/faster_csv.rb', line 267 def delete_if(&block) @row.delete_if(&block) self # for chaining end |
- (Object) each(&block)
Yields each pair of the row as header and field tuples (much like iterating over a Hash).
Support for Enumerable.
This method returns the row for chaining.
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# File 'lib/faster_csv.rb', line 342 def each(&block) @row.each(&block) self # for chaining end |
- (Object) field(header_or_index, minimum_index = 0) Also known as: []
:call-seq:
field( header ) field( header, offset ) field( index )
This method will fetch the field value by header or index. If a field is not found, nil is returned.
When provided, offset ensures that a header match occurrs on or later than the offset index. You can use this to find duplicate headers, without resorting to hard-coding exact indices.
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# File 'lib/faster_csv.rb', line 161 def field(header_or_index, minimum_index = 0) # locate the pair finder = header_or_index.is_a?(Integer) ? :[] : :assoc pair = @row[minimum_index..-1].send(finder, header_or_index) # return the field if we have a pair pair.nil? ? nil : pair.last end |
- (Boolean) field?(data)
Returns true if data matches a field in this row, and false otherwise.
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# File 'lib/faster_csv.rb', line 328 def field?(data) fields.include? data end |
- (Boolean) field_row?
Returns true if this is a field row.
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# File 'lib/faster_csv.rb', line 139 def field_row? not header_row? end |
- (Object) fields(*headers_and_or_indices) Also known as: values_at
This method accepts any number of arguments which can be headers, indices, Ranges of either, or two-element Arrays containing a header and offset. Each argument will be replaced with a field lookup as described in FasterCSV::Row.field().
If called with no arguments, all fields are returned.
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# File 'lib/faster_csv.rb', line 281 def fields(*headers_and_or_indices) if headers_and_or_indices.empty? # return all fields--no arguments @row.map { |pair| pair.last } else # or work like values_at() headers_and_or_indices.inject(Array.new) do |all, h_or_i| all + if h_or_i.is_a? Range index_begin = h_or_i.begin.is_a?(Integer) ? h_or_i.begin : index(h_or_i.begin) index_end = h_or_i.end.is_a?(Integer) ? h_or_i.end : index(h_or_i.end) new_range = h_or_i.exclude_end? ? (index_begin...index_end) : (index_begin..index_end) fields.values_at(new_range) else [field(*Array(h_or_i))] end end end end |
- (Boolean) header?(name) Also known as: include?
Returns true if name is a header for this row, and false otherwise.
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# File 'lib/faster_csv.rb', line 319 def header?(name) headers.include? name end |
- (Boolean) header_row?
Returns true if this is a header row.
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# File 'lib/faster_csv.rb', line 134 def header_row? @header_row end |
- (Object) headers
Returns the headers of this row.
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# File 'lib/faster_csv.rb', line 144 def headers @row.map { |pair| pair.first } end |
- (Object) index(header, minimum_index = 0)
:call-seq:
index( header ) index( header, offset )
This method will return the index of a field with the provided header. The offset can be used to locate duplicate header names, as described in FasterCSV::Row.field().
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# File 'lib/faster_csv.rb', line 311 def index(header, minimum_index = 0) # find the pair index = headers[minimum_index..-1].index(header) # return the index at the right offset, if we found one index.nil? ? nil : index + minimum_index end |
- (Object) inspect
A summary of fields, by header.
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# File 'lib/faster_csv.rb', line 376 def inspect str = "#<#{self.class}" each do |header, field| str << " #{header.is_a?(Symbol) ? header.to_s : header.inspect}:" << field.inspect end str << ">" end |
- (Object) push(*args)
A shortcut for appending multiple fields. Equivalent to:
args.each { |arg| faster_csv_row << arg }
This method returns the row for chaining.
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# File 'lib/faster_csv.rb', line 236 def push(*args) args.each { |arg| self << arg } self # for chaining end |
- (Object) to_csv(options = Hash.new) Also known as: to_s
Returns the row as a CSV String. Headers are not used. Equivalent to:
faster_csv_row.fields.to_csv( )
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# File 'lib/faster_csv.rb', line 370 def to_csv( = Hash.new) fields.to_csv() end |
- (Object) to_hash
Collapses the row into a simple Hash. Be warning that this discards field order and clobbers duplicate fields.
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# File 'lib/faster_csv.rb', line 360 def to_hash # flatten just one level of the internal Array Hash[*@row.inject(Array.new) { |ary, pair| ary.push(*pair) }] end |