Class: CSV::Row
- Inherits:
-
Object
- Object
- CSV::Row
- Extended by:
- Forwardable
- Includes:
- Enumerable
- Defined in:
- lib/csv.rb
Overview
A CSV::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 CSV will be constructed from this class, if header row processing is activated.
Instance Method Summary collapse
-
#<<(arg) ⇒ Object
:call-seq: <<( field ) <<( header_and_field_array ) <<( header_and_field_hash ).
-
#==(other) ⇒ Object
Returns
true
if this row contains the same headers and fields in the same order asother
. -
#[]=(*args) ⇒ Object
:call-seq: []=( header, value ) []=( header, offset, value ) []=( index, value ).
-
#delete(header_or_index, minimum_index = 0) ⇒ Object
:call-seq: delete( header ) delete( header, offset ) delete( index ).
-
#delete_if(&block) ⇒ Object
The provided
block
is passed a header and field for each pair in the row and expected to returntrue
orfalse
, depending on whether the pair should be deleted. -
#each(&block) ⇒ Object
Yields each pair of the row as header and field tuples (much like iterating over a Hash).
-
#field(header_or_index, minimum_index = 0) ⇒ Object
(also: #[])
:call-seq: field( header ) field( header, offset ) field( index ).
-
#field?(data) ⇒ Boolean
Returns
true
ifdata
matches a field in this row, andfalse
otherwise. -
#field_row? ⇒ Boolean
Returns
true
if this is a field row. -
#fields(*headers_and_or_indices) ⇒ Object
(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.
-
#header?(name) ⇒ Boolean
(also: #include?)
Returns
true
ifname
is a header for this row, andfalse
otherwise. -
#header_row? ⇒ Boolean
Returns
true
if this is a header row. -
#headers ⇒ Object
Returns the headers of this row.
-
#index(header, minimum_index = 0) ⇒ Object
:call-seq: index( header ) index( header, offset ).
-
#initialize(headers, fields, header_row = false) ⇒ Row
constructor
Construct a new CSV::Row from
headers
andfields
, which are expected to be Arrays. -
#inspect ⇒ Object
A summary of fields, by header, in an ASCII compatible String.
-
#push(*args) ⇒ Object
A shortcut for appending multiple fields.
-
#to_csv(options = Hash.new) ⇒ Object
(also: #to_s)
Returns the row as a CSV String.
-
#to_hash ⇒ Object
Collapses the row into a simple Hash.
Constructor Details
#initialize(headers, fields, header_row = false) ⇒ Row
Construct a new CSV::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 CSV::Row.header_row?() and CSV::Row.field_row?(), that this is a header row. Otherwise, the row is assumes to be a field row.
A CSV::Row object supports the following Array methods through delegation:
-
empty?()
-
length()
-
size()
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# File 'lib/csv.rb', line 236 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
#<<(arg) ⇒ Object
: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/csv.rb', line 340 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 |
#==(other) ⇒ Object
Returns true
if this row contains the same headers and fields in the same order as other
.
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# File 'lib/csv.rb', line 477 def ==(other) @row == other.row end |
#[]=(*args) ⇒ Object
:call-seq:
[]=( header, value )
[]=( header, offset, value )
[]=( index, value )
Looks up the field by the semantics described in CSV::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/csv.rb', line 307 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 |
#delete(header_or_index, minimum_index = 0) ⇒ Object
: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 CSV::Row.field(). The deleted pair is returned, or nil
if a pair could not be found.
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# File 'lib/csv.rb', line 375 def delete(header_or_index, minimum_index = 0) if header_or_index.is_a? Integer # by index @row.delete_at(header_or_index) elsif i = index(header_or_index, minimum_index) # by header @row.delete_at(i) else [ ] end end |
#delete_if(&block) ⇒ Object
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/csv.rb', line 392 def delete_if(&block) @row.delete_if(&block) self # for chaining end |
#each(&block) ⇒ Object
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/csv.rb', line 467 def each(&block) @row.each(&block) self # for chaining end |
#field(header_or_index, minimum_index = 0) ⇒ Object 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/csv.rb', line 284 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 |
#field?(data) ⇒ Boolean
Returns true
if data
matches a field in this row, and false
otherwise.
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# File 'lib/csv.rb', line 453 def field?(data) fields.include? data end |
#field_row? ⇒ Boolean
Returns true
if this is a field row.
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# File 'lib/csv.rb', line 262 def field_row? not header_row? end |
#fields(*headers_and_or_indices) ⇒ Object 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 CSV::Row.field().
If called with no arguments, all fields are returned.
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# File 'lib/csv.rb', line 406 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 |
#header?(name) ⇒ Boolean Also known as: include?
Returns true
if name
is a header for this row, and false
otherwise.
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# File 'lib/csv.rb', line 444 def header?(name) headers.include? name end |
#header_row? ⇒ Boolean
Returns true
if this is a header row.
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# File 'lib/csv.rb', line 257 def header_row? @header_row end |
#headers ⇒ Object
Returns the headers of this row.
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# File 'lib/csv.rb', line 267 def headers @row.map { |pair| pair.first } end |
#index(header, minimum_index = 0) ⇒ Object
: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 CSV::Row.field().
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# File 'lib/csv.rb', line 436 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 |
#inspect ⇒ Object
A summary of fields, by header, in an ASCII compatible String.
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# File 'lib/csv.rb', line 501 def inspect str = ["#<", self.class.to_s] each do |header, field| str << " " << (header.is_a?(Symbol) ? header.to_s : header.inspect) << ":" << field.inspect end str << ">" begin str.join('') rescue # any encoding error str.map do |s| e = Encoding::Converter.asciicompat_encoding(s.encoding) e ? s.encode(e) : s.force_encoding("ASCII-8BIT") end.join('') end end |
#push(*args) ⇒ Object
A shortcut for appending multiple fields. Equivalent to:
args.each { |arg| csv_row << arg }
This method returns the row for chaining.
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# File 'lib/csv.rb', line 359 def push(*args) args.each { |arg| self << arg } self # for chaining end |
#to_csv(options = Hash.new) ⇒ Object Also known as: to_s
Returns the row as a CSV String. Headers are not used. Equivalent to:
csv_row.fields.to_csv( )
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# File 'lib/csv.rb', line 495 def to_csv( = Hash.new) fields.to_csv() end |
#to_hash ⇒ Object
Collapses the row into a simple Hash. Be warning that this discards field order and clobbers duplicate fields.
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# File 'lib/csv.rb', line 485 def to_hash # flatten just one level of the internal Array Hash[*@row.inject(Array.new) { |ary, pair| ary.push(*pair) }] end |