ruby字元串處理函數

出處：http://blog.163.com/[email protected]/blog/static/2482210220100159515220/

1.傳回字元串的長度

str.length => integer

2.判斷字元串中是否包含另一個串

str.include? other_str => true or false

   "hello".include? "lo"   #=> true

   "hello".include? "ol"   #=> false

   "hello".include? ?h     #=> true

3.字元串插入:

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')

-3, 'X')   #=> "abXcd"

   "abcd".insert(-1, 'X')   #=> "abcdX"

4.字元串分隔,預設分隔符為空格

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,,"]

5.字元串替換

str.gsub(pattern, replacement) => new_str

str.gsub(pattern) {|match| block } => new_str

"hello".gsub(/[aeiou]/, '*')              #=> "h*ll*"     #将元音替換成*号

   "hello".gsub(/([aeiou])/, '<\1>')         #=> "h<e>ll<o>"   #将元音加上尖括号,\1表示保留原有字元???

   "hello".gsub(/./) {|s| s[0].to_s + ' '}   #=> "104 101 108 108 111 "

 字元串替換二:

str.replace(other_str) => str

   s = "hello"         #=> "hello"

   s.replace "world"   #=> "world"

6.字元串删除:

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.去掉前和後的空格

str.lstrip => new_str

   " hello ".lstrip   #=> "hello "

   "hello".lstrip       #=> "hello"

8.字元串比對

str.match(pattern) => matchdata or nil

9.字元串反轉

str.reverse => new_str

"stressed".reverse   #=> "desserts"

10.去掉重複的字元

str.squeeze([other_str]*) => new_str

"yellow moon".squeeze                  #=> "yelow mon" #預設去掉串中所有重複的字元

" now   is the".squeeze(" ")         #=> " now is the" #去掉串中重複的空格

"putters shoot balls".squeeze("m-z")   #=> "puters shot balls" #去掉指定範圍内的重複字元

11.轉化成數字

str.to_i=> str

"12345".to_i             #=> 12345

chomp和chop的差別:

chomp:去掉字元串末尾的\n或\r

chop:去掉字元串末尾的最後一個字元,不管是\n\r還是普通字元

"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"