字符串处理函数
1.返回字符串的长度
str.length => integer

2.判断字符串中是否包含另一个串
str.include? other_str => true or false
"hello".include? "lo"#=> true"hello".include? "ol"#=> false"hello".include? ?h     #=> true

3.字符串插入:
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str.insert(index, other_str) => str
"abcd".insert(0, 'X')    #=> "Xabcd""abcd".insert(3, 'X')    #=> "abcXd""abcd".insert(4, 'X')    #=> "abcdX""abcd".insert(-3, 'X')
-3, 'X')   #=> "abXcd""abcd".insert(-1, 'X')   #=> "abcdX"
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4.字符串分隔,默认分隔符为空格
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str.split(pattern=$;, [limit]) => anArray
" now's the time".split        #=> ["now's", "the", "time"]"1, 2.34,56, 7".split(%r{,\s*}) #=> ["1", "2.34", "56", "7"]"hello".split(//)               #=> ["h", "e", "l", "l", "o"]"hello".split(//, 3)            #=> ["h", "e", "llo"]"hi mom".split(%r{\s*})         #=> ["h", "i", "m", "o", "m"]"mellow yellow".split("ello")   #=> ["m", "w y", "w"]"1,2,,3,4,,".split(',')         #=> ["1", "2", "", "3", "4"]"1,2,,3,4,,".split(',', 4)      #=> ["1", "2", "", "3,4,,"]
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5.字符串替换
str.gsub(pattern, replacement) => new_str
str.gsub(pattern) {|match| block } => new_str
"hello".gsub(/[aeiou]/, '*')              #=> "h*ll*"     #将元音替换成*号"hello".gsub(/([aeiou])/, '<\1>')         #=> "h<e>ll<o>"   #将元音加上尖括号,\1表示保留原有字符???"hello".gsub(/./) {|s| s[0].to_s + ''}   #=> "104 101 108 108 111 "
字符串替换二:
str.replace(other_str) => str
s = "hello"#=> "hello"
s.replace "world"#=> "world"

6.字符串删除:
str.delete([other_str]+) => new_str
"hello".delete "l","lo"#=> "heo""hello".delete "lo"#=> "he""hello".delete "aeiou", "^e"#=> "hell""hello".delete "ej-m"#=> "ho"

7.去掉前和后的空格
str.lstrip => new_str
" hello ".lstrip   #=> "hello ""hello".lstrip       #=> "hello"

8.字符串匹配
str.match(pattern) => matchdata or nil

9.字符串反转
str.reverse => new_str
"stressed".reverse   #=> "desserts"

10.去掉重复的字符
str.squeeze([other_str]*) => new_str
"yellow moon".squeeze                  #=> "yelow mon" #默认去掉串中所有重复的字符" now   is the".squeeze("")         #=> " now is the" #去掉串中重复的空格"putters shoot balls".squeeze("m-z")   #=> "puters shot balls" #去掉指定范围内的重复字符

11.转化成数字
str.to_i=> str
".to_i             #=> 12345

chomp和chop的区别:
chomp:去掉字符串末尾的\n或\r
chop:去掉字符串末尾的最后一个字符,不管是\n\r还是普通字符
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"hello".chomp            #=> "hello""hello\n".chomp          #=> "hello""hello\r\n".chomp        #=> "hello""hello\n\r".chomp        #=> "hello\n""hello\r".chomp          #=> "hello""hello".chomp("llo")     #=> "he""string\r\n".chop   #=> "string""string\n\r".chop   #=> "string\n""string\n".chop     #=> "string""string".chop       #=> "strin"
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转载自：http://blog.163.com/ma95221@126/blog/static/2482210220100159515220/