Ruby 字串處理函式

字串處理函式

1.返回字串的長度

str.length => integer

2.判斷字串中是否包含另乙個串

str.include? other_str => true or

false
"hello
".include? "lo"
#=> true
"hello
".include? "ol"
#=> false
"hello
".include? ?h #
=> true

3.字串插入:

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) #
=> ["1", "2.34", "56", "7"]
"hello
".split(//) #
=> ["h", "e", "l", "l", "o"]
"hello
".split(//, 3) #
=> ["h", "e", "llo"]
"hi mom
".split(%r) #
=> ["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.字串替換

str.gsub(pattern, replacement) =>new_str

str.gsub(pattern) =>new_str
"hello
".gsub(/[aeiou]/, '
*') #
=> "h*ll*" #將母音替換成*號
"hello
".gsub(/([aeiou])/, '
<\1>
') #
=> "hll" #將母音加上尖括號,\1表示保留原有字元???
"hello
".gsub(/./) #
=> "104 101 108 108 111 "

字串替換二:

str.replace(other_str) =>str

s = "
hello"#
=> "hello"
s.replace "
world"#
=> "world"

6.字串刪除:

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.字串匹配

str.match(pattern) => matchdata or nil

9.字串反轉

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" #去掉指定範圍內的重複字元

11.轉化成數字

str.to_i=>str

"12345
".to_i #
=> 12345

chomp和chop的區別:

chomp:去掉字串末尾的\n或\r

chop:去掉字串末尾的最後乙個字元,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"

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