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没有什么特别的原因开学学习Ruby，只是从兴趣出发 Programming Ruby 2nd EditionRange转化为数组
很简单，to_a方法搞定：
r = 3..12
arr = r.to_a # [3,4,5,6,7,8,9,10,11,12]
digits = 0..9
digits.include?(5) -> true
digits.min -> 0
digits.max -> 9
digits.reject {|i| i < 5 } -> [5, 6, 7, 8, 9]
digits.each {|digit| dial(digit) } -> 0..9
('a'..'z').to_a.each{|i| puts i} #显示a到z的字符串
r1 = 3..6
r2 = 3...6 #....不包含上线6
r1a, r1b = r1.first, r1.last # 3, 6
r1c, r1d = r1.begin, r1.end # 3, 6
r2a, r2b = r2.begin, r2.end # 3, 6 (注意：不是3和5)
r1 = "7".."9"
r2 = "7".."10"
r1.each {|x| puts x } # 打印出7,8,9
r2.each {|x| puts x } # 未打印任何东西
##为什么会出现这样的情况？这是因为这里都是字符串，由于r1中，"7"比"9"小
所以，它是个合理的Range；而表达式r2中，"7"比"10"大，下限大于了上限，就不合理了。
r1 = 23456..34567
x = 14142
y = 31416
r1.include?(x) # false
r1.include?(y) # true
迭代器3.times { print "X " }
1.upto(5) {|i| print i, " " }
99.downto(95) {|i| print i, " " }
50.step(80, 5) {|i| print i, " " } #50至80之间步长5
数字a -> 97 #ASCII值 读取文件f=File.open("testfile")
f.each{|line| puts line}
f.close
Readingline=gets #从键盘输入负值给line print line #打印line Hash表histogram = Hash.new() #新建一个Hash表 histogram['key1'] -> 0 histogram['key1'] = histogram['key1'] + 1 histogram['key1'] -> 1 histogram.default = "hello" #没有定义的key会返回hello Arrayshift char=[a,b,b,c].shift #删除数组中的第一个字符 puts char # a [1,3,5,7,9].find{|v| v*v < 30 } #返回满足条件的第一个值
["H", "A", "L"].collect {|x| x.succ } #输下当前字符的下一字符
[1,3,5,7,9].each{|i| puts i } #遍历数组
[1,3,5,7].inject {|sum, element| sum+element} #数组求和
[1,3,5,7].inject {|product, element| product*element} #数组求积
a=Array.new #新建一个数组
a = [ 'ant', 'bee', 'cat', 'dog', 'elk' ]
a[0] -> "ant"
a[3] -> "dog"
# this is the same:
a = %w{ ant bee cat dog elk }
a[0] -> "ant"
a[3] -> "dog"
a.length -> 5 #数组长度，变量为字符串长度
变量全局变量 用$开头 person = "Tim" person.id -> 936870 person.class -> String person -> "Tim" #{..} → 可以在引号中引用变量值或 def say_goodnight(name)
result = "Good night, #{name.capitalize}" #.capitalize输出字符串首字母大写
return result
end
puts say_goodnight('uncle')
输出结果:
Good night, Uncle
Stringsqueeze 我们可以使用squeeze 方法来一处重复的字符
s1 = "bookkeeper"
puts s2 = s1.squeeze # "bokeper"
s3 = "Hello..."
puts s4 = s3.squeeze # "Helo."
#If a parameter is specified, only those characters will be squeezed.
puts s5 = s3.squeeze(".") # "Hello."
将一个字符串按照单词进行反转，那么你就会用到split方法和，数组的reverse方法 phrase = "Now here's a sentence"
puts phrase.split(" ").reverse.join(" ")
# "sentence a here's Now"
strip strip将会删除掉字符串的开头和结尾的空格 sss="a d c " puts sss.strip => abc 如果你只想从字符串的开头或者结尾的空格，那么可以使用lstrip或者rstrip str = " abc " s2 = str.lstrip # "abc " s3 = str.rstrip # " abc" chop chop方法将会删除最后一个字符，返回新的string。如果字符是以\r\n结束，则两个字符都会被删除 str = "abcxyz" s1 = str.chop # "abcxy" str2="abc\r\n" s2=str2.chop #abc chomp str = "abcxyz"
puts s1 = str.chomp #abcxyz
str2 = "123\n"
puts s2=str2.chomp #123
str1 = "abcxyz"
str2 = "abcxyz"
puts s1 = str1.chomp("yz") # "abcx"
puts s2 = str2.chomp("x") # "abcxyz" #只匹配结尾的词
unpack puts "E".unpack("c") #69 输出一个字符串的asc码值
? puts "a"<<111 <<符号或者chr来把一个asc转换为字符串: puts 111.chr scan "hello world".scan(/./){|s| print s} #扫描匹配的字符串并打印
casecmp n4 = "ABC".casecmp("abc") # 0 功能同<=>忽略大小写
puts str="bobo" puts str.ljust(8,"++") #左对齐其余用++补齐 puts str.rjust(8,"++") #右对齐其余用++补齐 "Seconds/day: #{24*60*60}" -> Seconds/day: 86400
"#{'Ho! '*3}Merry Christmas!" -> Ho! Ho! Ho! Merry Christmas!
"This is line #$." -> This is line 3 # #?显示程序块中语句所在的行号
each_byte str="bobo"
str.each_byte{|byte| puts byte.chr}
结果：
b
o
b
o
dup person1 = "Tim" person2 = person1.dup #同.new功能相同也可以用person2=person1 person1[0] = "J" person1 -> "Jim" person2 -> "Tim" freeze person1 = "Tim" person2 = person1 person1.freeze # 字符串不可变 person2[0] = "J" 结果： prog.rb:4:in `[]=': can't modify frozen string (TypeError) from prog.rb:4 index & rindex index方法返回指定的子字符串，正则表达式或者字符的起始位置(如果有多个匹配的只返回第一个匹配的起始位置)
没有发现的话返回nil,而rindex则是从string的右边(也就是结束处)开始查找，不过返回的值却是从左边数起的：
str = "Albert Einstein"
puts pos1 = str.index(?E) # 7
puts pos1 = str.index(69) # 7
puts pos2 = str.index("bert") # 2
puts pos3 = str.index(/in/) # 8
puts pos4 = str.index(?e) # nil
puts pos5 = str.index("bart") # nil
puts pos6 = str.index(/wein/) # nil
正侧表达式 sub或者gsub方法来进行替换，他们两个方法第一个参数都是接受正则表达式。
其中，sub方法替换掉第一个匹配的地方，而gsub方法替换掉全部匹配的地方：
s1 = "spam, spam, and eggs"
s2 = s1.sub(/spam/,"bacon") # "bacon, spam, and eggs"
s3 = s2.sub(/(\w+), (\w+),/,'\2, \1,') # "spam, bacon, and eggs"
s4 = "Don't forget the spam."
s5 = s4.sub(/spam/) { |m| m.reverse } # "Don't forget the maps." 把匹配部分的单词反转
s5 = "alfalfa abracadabra"
s6 = s5.gsub(/a[bl]/,"xx") # "xxfxxfa xxracadxxra"
s5.gsub(/[lfdbr]/) { |m| m.upcase + "-" }
# s5 is now "aL-F-aL-F-a aB-R-acaD-aB-R-a"
String类常用函数表
基础ruby打印输出命令 puts 带换行符输出 priint 不带换行符输出 ruby中区间表示 1..5表示1，2，3，4，5 1...5表示1，2，3，4 /home1/yepnnet/public_html/wiki/data/attic/ruby.1223652031.txt.gz · 最后更改: 2008/10/10 09:20 由 admin |
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