比较两个单词（字符串）

Question

What does this code mean?

if( item.compareTo(root.element) < 0 ){

   }

I read that:

"Compares two strings lexicographically. Returns an integer indicating whether this string is greater than (result is > 0), equal to (result is = 0), or less than (result is < 0) the argument."

But I don't don't get it. Can someone explain with an example please?

Answer 1

Take a look at the documentation of the Comparable interface, which defines the compareTo() method in the first place. The implementation of this interface in String follows the same conventions:

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object

This means: if the current string is less than the string received as parameter (under the lexicographical order ) return a negative integer value. If the current string is greater than the string received as parameter, return a positive integer value. Otherwise, the strings are equal and 0 is returned.

Answer 2

someObject . compareTo ( anotherObject ) returns a negative number if someObject comes before anotherObject .

Here's an example that compares String objects:

if ("apple".compareTo("zebra") < 0) {
    System.out.println("I will be printed");
}
else {
    System.out.println("I will NOT be printed");
}

Answer 3

您可以在排序代码时使用它来查看item属于root.element之前。

Answer 4

it checks if two Strings are equal like this.

a>A  would return a positive number as `a` is greater than `A`
A>a  would return a negetive number as `A` is less than `a`
a==a would return 0 as `a` is equal to `a`
a>Z  would return a positive number as 'a' is greater than 'A'
trend> zend would return a positive number as `t` is greater than 'z'   

Answer 5

如果word1 = item，word2 = root.element并且两者都在字典中，则word1应出现在word2之前。