?

對象內容判斷.

nil? 和 false 對象 ,返回 true.

數值 和 TRUE 則始終返回 false.

其它對象,如為空時,返回 true,

如對象是字符串,會先剝離前后空格,再進行檢查是否為空.

?

?

puts [ ].blank????????????????????????????????? #=> true

puts { 1 =>2}.blank?????????????????????? #=>false

puts "cat".blank????????????????????????????? #=>false

puts "".blank?????????????????????????????????? #=>true

puts "?? ".blank??????????????????????????????? #=>true

puts nil.blank?????????????????????????????????? #=>true

?

?

枚舉與數組.Enumerations and Arrays

?

groups = posts.group_by {post|post.author_id}

?

us_states = state.find(:all)

state_lookup = us_states.index_by(|state| state.short_name)

?

?

puts[ "ant", "bat", "cat"].to_sentence #=>"ant,bat,and cat"

puts[ "ant", "bat", "cat"].to_sentence(:connector=> "andnotforgetting")
#=>"ant,bat,and not forgetting cat"

puts[ "ant", "bat", "cat"].to_sentence(:skip_last_comma=> true)
#=>"ant,bat and cat"
[1,2,3,4,5,6,7].in_groups_of(3) {|slice|putsslice.inspect}
#=>[1,2,3]
[4,5,6]
[7,nil, nil]

[1,2,3,4,5,6,7].in_groups_of(3,"X"){|slice|putsslice.inspect}
#=>[1,2,3]
[4,5,6]
[7,"X", "X"]

?

字符串擴展?? String? Extensions

?

string= "Nowisthetime"
putsstring.at(2) #=>"w"
putsstring.from(8) #=>"hetime"
putsstring.to(8) #=>"Nowisth"
putsstring.first #=>"N"
putsstring.first(3) #=>"Now"
putsstring.last #=>"e"
putsstring.last(4) #=>"time"
putsstring.starts_with?("No") #=>true
putsstring.ends_with?("ME") #=>false
count=Hash.new(0)
string.each_char{|ch|count[ch]+=1}
putscount.inspect
#=>{""=>3,"w"=>1,"m"=>1,"N"=>1,"o"=>1,
"e"=>2, "h"=>1, "s"=>1, "t"=>2, "i"=>2}

?

puts "cat".pluralize #=>cats
puts "cats".pluralize #=>cats
puts "erratum".pluralize #=>errata
puts "cats".singularize #=>cat
puts "errata".singularize #=>erratum
puts "first_name".humanize #=>"Firstname"
puts "nowisthetime".titleize #=>"NowIsTheTime"

?

depot> rubyscript/console
Loadingdevelopmentenvironment(Rails2.1).
>>"goose".pluralize
=>"gooses"

?

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