java - 如何检查单个字符是否出现在字符串中？(How can I check if a single character appears in a string?)

Question

In Java is there a way to check the condition:

(在Java中有一种方法来检查条件：)

"Does this single character appear at all in string x"

(“这个单个字符是否出现在字符串x中”)

without using a loop?

(没有使用循环？)

  ask by barfoon translate from so

Answer 1

You can use string.indexOf('a') .

(你可以使用string.indexOf('a') 。)

If the 'a' is present in string , it returns the index(>=0).

(如果string存在'a' ，则返回索引（> = 0）。)

If not, it returns -1.

(如果不是，则返回-1。)

So, a non-negative return value means that 'a' is present in the string .

(因此，非负返回值意味着'a' is present in the string 。)