* lib/csv.rb: Added more Hash methods to CSV::Row.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38633 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 37 insertions, 1 deletions

diff --git a/lib/csv.rb b/lib/csv.rb
index a0209223c2..279890e7e0 100644
--- a/lib/csv.rb
+++ b/lib/csv.rb
@@ -274,7 +274,7 @@ class CSV
     #   field( header, offset )
     #   field( index )
     #
-    # This method will fetch the field value by +header+ or +index+.  If a field
+    # 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 occurrs on or later
@@ -293,6 +293,42 @@ class CSV
 
     #
     # :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?
+
+    #
+    # :call-seq:
     #   []=( header, value )
     #   []=( header, offset, value )
     #   []=( index, value )