blocks|key|3001511|text|参见the+javadoc。它是第一个参数的包含索引，第二个参数是独占索引。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3001512|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring%2528int,%2520int%2529^0|2|B|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

See <a href="http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring%28int,%20int%29" rel="nofollow noreferrer">the javadoc</a>. It's an inclusive index for the first argument and exclusive for the second.

blocks|key|3214836|text|两者都是从0开始的，但是开始是包含的，结束是排他的。这确保了结果字符串的长度为start+-+end。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3214837|为了使substring操作变得更容易，假设索引之间有字符。|3214838|0+1+2+3+4+5+6+7+8+9+10++<-+available+indexes+for+substring+
+u+n+i+v+E+R+S+i+t+y
++++++++↑+++++↑
++++++start++end+-->+range+of+"E+R+S"|code-block|syntax|javascript|3214839|引用docs|3214840|3214841|子字符串从指定的beginIndex开始，延伸到索引endIndex+-+1处的字符。因此，子字符串的长度为endIndex-beginIndex。|blockquote|3214842|3214843|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring%2528int%252c%2520int%2529^0|13|B|0|3|9|0|0|2|4|0|0|0|8|A|Q|C|1I|J|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|17|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|18|8|@]|D|@$9|19|A|1A|1|1B]]|E|$]]|$1|O|3|-4|5|6|7|1C|8|@]|D|@]|E|$]]|$1|P|3|Q|5|R|7|1D|8|@$9|1E|A|1F|B|C]|$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1K|8|@]|D|@]|E|$]]|$1|T|3|-4|5|6|7|1L|8|@]|D|@]|E|$]]]|U|$V|$5|W|X|Y|E|$Z|10]]]]

Both are 0-based, but the start is inclusive and the end is exclusive. This ensures the resulting string is of length <code>start - end</code>. 

To make life easier for <code>substring</code> operation, imagine that characters are between indexes.

<pre><code>0 1 2 3 4 5 6 7 8 9 10 &lt;- available indexes for substring 
 u n i v E R S i t y
 ↑ ↑
 start end --&gt; range of "E R S"
</code></pre>

Quoting the <a href="http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring%28int%2c%20int%29" rel="nofollow noreferrer">docs</a>:

<blockquote>
 The substring begins at the specified
 <code>beginIndex</code> and extends to the
 character at index <code>endIndex - 1</code>. Thus
 the length of the substring is
 <code>endIndex-beginIndex</code>.
</blockquote>

blocks|key|289530|text|是的，索引从零(0)开始。这两个参数是startIndex和endIndex，根据文档：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|289531|289532|子字符串从指定的beginIndex开始，延伸到索引endIndex+-+1处的字符。|blockquote|289533|289534|289535|有关详细信息，请参阅here。|offset|length|289536|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/1.5.0/docs/api/java/lang/String.html#substring%2528int,%2520int%2529^0|0|0|0|0|0|A|4|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|U|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|V|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|W|8|@]|9|@]|A|$]]|$1|G|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|Y|8|@]|9|@$J|Z|K|10|1|11]]|A|$]]|$1|L|3|-4|5|6|7|12|8|@]|9|@]|A|$]]]|M|$N|$5|O|P|Q|A|$R|S]]]]

Yes, the index starts at zero (0). The two arguments are startIndex and endIndex, where per the documentation:

<blockquote>
 The substring begins at the specified beginIndex and extends to the character at index endIndex - 1.
</blockquote>

See <a href="http://download.oracle.com/javase/1.5.0/docs/api/java/lang/String.html#substring%28int,%20int%29" rel="nofollow noreferrer">here</a> for more information.

blocks|key|289538|text|0:+U|type|unstyled|depth|inlineStyleRanges|entityRanges|data|289539|1:+N|289540|2:我|289541|3:+v|289542|4:+e|offset|length|style|BOLD|289543|5:+r|289544|6:+s|289545|7:我|289546|8:+T|289547|9:+Y|289548|起始索引是包含索引|289549|结束索引是独占的|289550|Javadoc+link|289551|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring(int,%2520int)^0|0|0|0|0|0|4|0|0|4|0|0|4|0|0|0|0|0|0|0|C|0|0^^$0|@$1|2|3|4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|1C|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1D|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|1E|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|1F|8|@$J|1G|K|1H|L|M]]|9|@]|A|$]]|$1|N|3|O|5|6|7|1I|8|@$J|1J|K|1K|L|M]]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1L|8|@$J|1M|K|1N|L|M]]|9|@]|A|$]]|$1|R|3|S|5|6|7|1O|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|1P|8|@]|9|@]|A|$]]|$1|V|3|W|5|6|7|1Q|8|@]|9|@]|A|$]]|$1|X|3|Y|5|6|7|1R|8|@]|9|@]|A|$]]|$1|Z|3|10|5|6|7|1S|8|@]|9|@]|A|$]]|$1|11|3|12|5|6|7|1T|8|@]|9|@$J|1U|K|1V|1|1W]]|A|$]]|$1|13|3|-4|5|6|7|1X|8|@]|9|@]|A|$]]]|14|$15|$5|16|17|18|A|$19|1A]]]]

0: U

1: n

2: i

3: v

4: e

5: r

6: s

7: i

8: t

9: y

Start index is inclusive

End index is exclusive

<a href="http://download.oracle.com/javase/6/docs/api/java/lang/String.html#substring(int,%20int)" rel="noreferrer">Javadoc link</a>

blocks|key|3001675|text|像你一样，我发现这不是自然而然的。我通常还是要提醒自己|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3001676|3001677|返回的字符串长度为|unordered-list-item|3001678|3001679|lastIndex+-+firstIndex|3001680|that您可以使用字符串的长度作为lastIndex，即使其中没有字符并且尝试引用它会抛出异常|3001681|3001682|所以|3001683|"University".substring(6,+10)|code-block|syntax|javascript|3001684|返回4个字符的字符串“即使位置10处没有字符，也返回sity"。|offset|length|style|CODE|3001685|entityMap^0|0|0|0|0|0|0|0|0|0|Q|5|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|11|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|12|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|14|8|@]|9|@]|A|$]]|$1|I|3|J|5|E|7|15|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|16|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|17|8|@]|9|@]|A|$]]|$1|N|3|O|5|P|7|18|8|@]|9|@]|A|$Q|R]]|$1|S|3|T|5|6|7|19|8|@$U|1A|V|1B|W|X]]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1C|8|@]|9|@]|A|$]]]|Z|$]]

Like you I didn't find it came naturally. I normally still have to remind myself that

<ul>
<li>the length of the returned string is 

lastIndex - firstIndex</li>
<li>that you can use the length of the string as the lastIndex even though there is no character there and trying to reference it would throw an Exception</li>
</ul>

so 

<pre><code>"University".substring(6, 10)
</code></pre>

returns the 4-character string "<code>sity"</code> even though there is no character at position 10.

blocks|key|284101|text|对于子字符串(+startIndex，endIndex)，startIndex是包含的，endIndex是排除的。startIndex和endIndex非常容易混淆。我会理解substring(startIndex，length)来记住这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|284102|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

For substring(startIndex, endIndex), startIndex is inclusive and endIndex are exclusive. The startIndex and endIndex are very confusing.
I would understand substring(startIndex, length) to remember that.

blocks|key|286332|text|子字符串从开始，包括给定的第一个数字所在位置的字符，然后转到，但不包括给定的最后一个数字所在的字符。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|286333|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The substring starts at, and includes the character at the location of the first number given and goes to, but does not include the character at the last number given.

blocks|key|286341|text|public+String+substring(int+beginIndex,+int+endIndex)|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|286342|beginIndex-the开始索引，包括在内。|unstyled|offset|length|style|CODE|286343|endIndex-the结束索引，独占。|286344|示例：|286345|public+class+Test+{

++++public+static+void+main(String+args[])+{
++++++++String+Str+=+new+String("Hello+World");

++++++++System.out.println(Str.substring(3,+8));
++++}
+}|286346|输出："lo“|286347|从3到7个索引。|286348|还有另一种substring()方法：|286349|public+String+substring(int+beginIndex)|286350|beginIndex-the开始索引，包括在内。返回从beginIndex开始到主字符串末尾的子字符串。|286351|286352|public+class+Test+{

++++public+static+void+main(String+args[])+{
++++++++String+Str+=+new+String("Hello+World");

++++++++System.out.println(Str.substring(3));
++++}
}|286353|286354|从3到最后一个索引。|286355|entityMap^0|0|0|A|0|0|8|0|0|0|0|0|5|B|0|0|0|A|R|A|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|18|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|19|8|@$G|1A|H|1B|I|J]]|9|@]|A|$]]|$1|K|3|L|5|F|7|1C|8|@$G|1D|H|1E|I|J]]|9|@]|A|$]]|$1|M|3|N|5|F|7|1F|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1G|8|@]|9|@]|A|$B|C]]|$1|Q|3|R|5|F|7|1H|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|1I|8|@]|9|@]|A|$]]|$1|U|3|V|5|F|7|1J|8|@$G|1K|H|1L|I|J]]|9|@]|A|$]]|$1|W|3|X|5|6|7|1M|8|@]|9|@]|A|$B|C]]|$1|Y|3|Z|5|F|7|1N|8|@$G|1O|H|1P|I|J]|$G|1Q|H|1R|I|J]]|9|@]|A|$]]|$1|10|3|N|5|F|7|1S|8|@]|9|@]|A|$]]|$1|11|3|12|5|6|7|1T|8|@]|9|@]|A|$B|C]]|$1|13|3|R|5|F|7|1U|8|@]|9|@]|A|$]]|$1|14|3|15|5|F|7|1V|8|@]|9|@]|A|$]]|$1|16|3|-4|5|F|7|1W|8|@]|9|@]|A|$]]]|17|$]]

<pre><code>public String substring(int beginIndex, int endIndex)
</code></pre>

<code>beginIndex</code>—the begin index, inclusive.

<code>endIndex</code>—the end index, exclusive.

Example:

<pre><code>public class Test {

 public static void main(String args[]) {
 String Str = new String("Hello World");

 System.out.println(Str.substring(3, 8));
 }
 }
</code></pre>

Output: "lo Wo" 

From 3 to 7 index.

Also there is another kind of <code>substring()</code> method:

<pre><code>public String substring(int beginIndex)
</code></pre>

<code>beginIndex</code>—the begin index, inclusive.
Returns a sub string starting from <code>beginIndex</code> to the end of the main String.

Example:

<pre><code>public class Test {

 public static void main(String args[]) {
 String Str = new String("Hello World");

 System.out.println(Str.substring(3));
 }
}
</code></pre>

Output: "lo World" 

From 3 to the last index.

blocks|key|287244|text|public+class+SubstringExample
{
++++public+static+void+main(String[]+args)+
++++{
++++++++String+str="OOPs+is+a+programming+paradigm...";

++++++++System.out.println("+Length+is:+"+%2B+str.length());

++++++++System.out.println("+Substring+is:+"+%2B+str.substring(10,+30));
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|287245|输出：|unstyled|287246|length+is:+31

Substring+is:+programming+paradigm|287247|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|L|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|I|3|-4|5|F|7|N|8|@]|9|@]|A|$]]]|J|$]]

<pre><code>public class SubstringExample
{
 public static void main(String[] args) 
 {
 String str="OOPs is a programming paradigm...";

 System.out.println(" Length is: " + str.length());

 System.out.println(" Substring is: " + str.substring(10, 30));
 }
}
</code></pre>

Output:

<pre><code>length is: 31

Substring is: programming paradigm
</code></pre>

Code:

<pre><code>public class Test {
 public static void main(String[] args) {
 String str = "University";
 System.out.println(str.substring(4, 7));
 } 
}
</code></pre>

Output: <code>ers</code>

I do not really understand how the substring method works. Does the index start at 0? If I start with 0, <code>e</code> is at index 4 but char <code>i</code> is at 7 so the output would be <code>ersi</code>.

substring index range

代码：public class Test {    public static void main(String[] args) {        String str = "University";        System.out.println(str.substring(4, 7));    }   }输出：...

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