| Current File : //opt/alt/ruby27/share/ruby/csv/row.rb |
# frozen_string_literal: true
require "forwardable"
class CSV
#
# 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.
#
class Row
#
# Constructs 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 assumes to be a field row.
#
# A CSV::Row object supports the following Array methods through delegation:
#
# * empty?()
# * length()
# * size()
#
def initialize(headers, fields, header_row = false)
@header_row = header_row
headers.each { |h| h.freeze if h.is_a? String }
# handle extra headers or fields
@row = if headers.size >= fields.size
headers.zip(fields)
else
fields.zip(headers).each(&:reverse!)
end
end
# Internal data format used to compare equality.
attr_reader :row
protected :row
### Array Delegation ###
extend Forwardable
def_delegators :@row, :empty?, :length, :size
def initialize_copy(other)
super
@row = @row.dup
end
# Returns +true+ if this is a header row.
def header_row?
@header_row
end
# Returns +true+ if this is a field row.
def field_row?
not header_row?
end
# Returns the headers of this row.
def headers
@row.map(&:first)
end
#
# :call-seq:
# field( header )
# field( header, offset )
# field( index )
#
# This method will return the field value by +header+ or +index+. If a field
# is not found, +nil+ is returned.
#
# When provided, +offset+ ensures that a header match occurs on or later
# than the +offset+ index. You can use this to find duplicate headers,
# without resorting to hard-coding exact indices.
#
def field(header_or_index, minimum_index = 0)
# locate the pair
finder = (header_or_index.is_a?(Integer) || header_or_index.is_a?(Range)) ? :[] : :assoc
pair = @row[minimum_index..-1].send(finder, header_or_index)
# return the field if we have a pair
if pair.nil?
nil
else
header_or_index.is_a?(Range) ? pair.map(&:last) : pair.last
end
end
alias_method :[], :field
#
# :call-seq:
# fetch( header )
# fetch( header ) { |row| ... }
# fetch( header, default )
#
# This method will fetch the field value by +header+. It has the same
# behavior as Hash#fetch: if there is a field with the given +header+, its
# value is returned. Otherwise, if a block is given, it is yielded the
# +header+ and its result is returned; if a +default+ is given as the
# second argument, it is returned; otherwise a KeyError is raised.
#
def fetch(header, *varargs)
raise ArgumentError, "Too many arguments" if varargs.length > 1
pair = @row.assoc(header)
if pair
pair.last
else
if block_given?
yield header
elsif varargs.empty?
raise KeyError, "key not found: #{header}"
else
varargs.first
end
end
end
# Returns +true+ if there is a field with the given +header+.
def has_key?(header)
!!@row.assoc(header)
end
alias_method :include?, :has_key?
alias_method :key?, :has_key?
alias_method :member?, :has_key?
alias_method :header?, :has_key?
#
# :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 <tt>[nil, nil]</tt>. Assigning to an unused header appends the new
# pair.
#
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
#
# :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.
#
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
#
# A shortcut for appending multiple fields. Equivalent to:
#
# args.each { |arg| csv_row << arg }
#
# This method returns the row for chaining.
#
def push(*args)
args.each { |arg| self << arg }
self # for chaining
end
#
# :call-seq:
# delete( header )
# delete( header, offset )
# delete( index )
#
# Removes 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.
#
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
#
# 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.
#
# If no block is given, an Enumerator is returned.
#
def delete_if(&block)
return enum_for(__method__) { size } unless block_given?
@row.delete_if(&block)
self # for chaining
end
#
# 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.
#
def fields(*headers_and_or_indices)
if headers_and_or_indices.empty? # return all fields--no arguments
@row.map(&:last)
else # or work like values_at()
all = []
headers_and_or_indices.each do |h_or_i|
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)
all.concat(fields.values_at(new_range))
else
all << field(*Array(h_or_i))
end
end
return all
end
end
alias_method :values_at, :fields
#
# :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().
#
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
#
# Returns +true+ if +data+ matches a field in this row, and +false+
# otherwise.
#
def field?(data)
fields.include? data
end
include Enumerable
#
# Yields each pair of the row as header and field tuples (much like
# iterating over a Hash). This method returns the row for chaining.
#
# If no block is given, an Enumerator is returned.
#
# Support for Enumerable.
#
def each(&block)
return enum_for(__method__) { size } unless block_given?
@row.each(&block)
self # for chaining
end
alias_method :each_pair, :each
#
# Returns +true+ if this row contains the same headers and fields in the
# same order as +other+.
#
def ==(other)
return @row == other.row if other.is_a? CSV::Row
@row == other
end
#
# Collapses the row into a simple Hash. Be warned that this discards field
# order and clobbers duplicate fields.
#
def to_h
hash = {}
each do |key, _value|
hash[key] = self[key] unless hash.key?(key)
end
hash
end
alias_method :to_hash, :to_h
alias_method :to_ary, :to_a
#
# Returns the row as a CSV String. Headers are not used. Equivalent to:
#
# csv_row.fields.to_csv( options )
#
def to_csv(**options)
fields.to_csv(**options)
end
alias_method :to_s, :to_csv
#
# Extracts the nested value specified by the sequence of +index+ or +header+ objects by calling dig at each step,
# returning nil if any intermediate step is nil.
#
def dig(index_or_header, *indexes)
value = field(index_or_header)
if value.nil?
nil
elsif indexes.empty?
value
else
unless value.respond_to?(:dig)
raise TypeError, "#{value.class} does not have \#dig method"
end
value.dig(*indexes)
end
end
#
# A summary of fields, by header, in an ASCII compatible String.
#
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
end
end