ruby字符串处理函数
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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:
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')?? #=> "abXcd"
?? "abcd".insert(-1, 'X')?? #=> "abcdX"
4.字符串分隔,默认分隔符为空格
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
"12345".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
"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"
?? "x".chop.chop?????? #=> ""
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