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字符串中删去多余的空格保留二个,空格分割

在C#的字符串,其中有许多空格,现要求是把多余的空格去除保留一个。原理是使用Split()方法进行分割,分割有一个选项是RemoveEmptyEntries,然后再把分割后的字符串Join起来。
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JAVA 一个或多个空格分割字符串

1.返回字符串的长度

str.length => integer

 

知识补充

  1. String的split方法支持正则表达式;

  2. 正则表达式\s表示匹配任何空白字符,+表示匹配一次或多次。

有了以上补充知识,下面的内容就很好理解了。

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

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一、待分割字符串

待分割字符串为如下:

String str = "a  b     c  d e f      g"

其中,字符串中的的空白分别为:单个空格,多个空格,tab制表符。

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"
string string1 = "AAaaA     Oopps   32  211  44.8 69     15.9         C#        36.7 0.6  ";

            string[] arr = string1.Trim().Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries);
            string result = string.Join(" ", arr);
            Console.WriteLine(result);

二、使用一个或多个空格分割字符串

正确代码如下:

String [] arr = str.split("\\s+");
for(String ss : arr){
    System.out.println(ss);
}

作为对比,错误代码如下:

String [] arr2 = str.split(" ");
for(String ss : arr2){
    System.out.println(ss);
}

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,,"]

Source Code

三、分割结果

使用正确代码分割结果:

a
b
c
d
e
f
g

使用错误代码分割结果:

a

b




c

d
e
f





g

  public static void main(String args[]) {

        String line = "good12 morning34 good56 night78";

        //对String进行split之后的数组的输出
        String[] tt=line.split("\\s+");
        for(String s:tt)
        {
            System.out.println(s);
        }
        System.out.println("#####");
}

输出结果为
good12
morning34
good56
night78

 

 

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 ".rstrip   #=> " hello"
" hello ".strip #=> "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"

String#split

str.split(pattern=$;, [limit]) => anArray

将一个字符串用分隔符分割成一些子字符串,并返回一个包含这些子字符串的数组。
如果PATTERN部分是一个字符串,那么用它作分割符来分隔,如果PATTERN是一个空格,那么在空格处分割,并且临近的空格被忽略。
如果PATTERN是个正则表达式,那么在匹配PATTERN的地方分割,当PATTERN是长度为0的字符串,那么SPLIT将把字符串分割为单个字符
如果PATTERN被忽略,将用$;来分隔,如果$;没有设置(就是在默认状态),SPLIT将制定空格’

如果LIMIT参数被忽略,跟踪空段被抑制,如果LIMIT是个正数,那么至多返回LIMIT个字段(如果是1,那么将整个字符串作为一个字段返回),如果是个负数,那么跟踪空段不被抑制。

" now's the time".split #=> ["now's", "the", "time"]
" now's the time".split(' ') #=> ["now's", "the", "time"]
" 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,,"]
"1,2,,3,4,,".split(',', -4) #=> ["1", "2", "", "3", "4", "", ""]

如果包含特殊字符,注意转义

"wo | shi | yi | ge | bing".split(/\s*\|\s*) #竖杠别忘了转义

和String.scan的区别

split中的pattern是分隔符,而scan中的pattern指的是要匹配的东西

"123=342=4234=523421=6424".scan(/\d+/) #=> ["123","342","4234","523421","6424"]

如果匹配项被括起来,那么则会保留分割符,例如: ##

"Three little words".split(/\s+/) #===>["three","little",words"]
"Three little words".split(/(\s+)/) #===>["three"," ","little"," ","words"] 保留了空格