比较Java中的字符 [英] Comparing chars in Java

问题描述

我想检查一个字符变量是否是一个字符串，因为我已经做了任何Java，所以我的语法不是最大的。

例如：

  if（symbol ==（'A'|'B'|'C'））{} 
  

b $ b

似乎不工作。我需要像这样写：

  if（symbol =='A'|| symbol =='B' ）
  

解决方案

如果输入是字符，正在检查是否大致连续，您可以尝试这样：

  if（（symbol> ='A'&& < ='Z'）|| symbol =='？'）{
 // ... 
} 
  

---

然而，如果你的输入是一个字符串，一个更紧凑的方法（但是更慢）是使用一个带有字符类的正则表达式：

  if（symbol.matches（[AZ？]））{
 // ... 
} 
  

如果你有一个字符，你首先需要将它转换为字符串，然后才能使用正则表达式：

  if（Character.toString（symbol）.matches（[AZ？]））{
 // ... 
} 
  

It's been a while since I've done any Java so my syntax is not the greatest at the moment.

I want to check a char variable is one of 21 specific chars, what is the shortest way I can do this?

For example:

if(symbol == ('A'|'B'|'C')){}

Doesn't seem to be working. Do I need to write it like:

if(symbol == 'A' || symbol == 'B' etc.)

解决方案

If your input is a character and the characters you are checking against are mostly consecutive you could try this:

if ((symbol >= 'A' && symbol <= 'Z') || symbol == '?') {
    // ...
}

---

However if your input is a string a more compact approach (but slower) is to use a regular expression with a character class:

if (symbol.matches("[A-Z?]")) {
    // ...
}

If you have a character you'll first need to convert it to a string before you can use a regular expression:

if (Character.toString(symbol).matches("[A-Z?]")) {
    // ...
}

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