Java中的字符串比较 [英] String Comparison in Java

问题描述

按字典顺序比较两个字符串是什么意思？

What does "compare two strings lexicographically" mean?

推荐答案

来自@Bozho和@aioobe的答案，词典比较类似于字典中可能找到的排序。

Leading from answers from @Bozho and @aioobe, lexicographic comparisons are similar to the ordering that one might find in a dictionary.

Java String类提供 .compareTo（）方法以字典顺序比较字符串。它像这样使用apple.compareTo（banana）。

The Java String class provides the .compareTo () method in order to lexicographically compare Strings. It is used like this "apple".compareTo ("banana").

此方法的返回是一个 int ，可以解释如下：

The return of this method is an int which can be interpreted as follows:

• 返回< 0然后调用方法的String首先按字典顺序排在第一位（在字典中排在第一位）


• 返回== 0然后两个字符串按字典顺序相同


• 返回> 0然后传递给 compareTo 方法的参数首先按字典顺序排列。

• returns < 0 then the String calling the method is lexicographically first (comes first in a dictionary)
• returns == 0 then the two strings are lexicographically equivalent
• returns > 0 then the parameter passed to the compareTo method is lexicographically first.

更具体地说，该方法提供了ASCII值的第一个非零差异。

More specifically, the method provides the first non-zero difference in ASCII values.

因此computer.compareTo（comparison）将返回值（int）'u' - （int）'a'（21）。由于这是一个积极的结果，参数（比较）首先按字典顺序排列。

Thus "computer".compareTo ("comparison") will return a value of (int) 'u' - (int) 'a' (21). Since this is a positive result, the parameter ("comparison") is lexicographically first.

还有一个variant .compareToIgnoreCase（）将返回 0 a.compareToIgnoreCase（A ）; 例如。

There is also a variant .compareToIgnoreCase () which will return 0 for "a".compareToIgnoreCase ("A"); for example.

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