Java CompareToIgnoreCase
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Java CompareToIgnoreCase
提问by user1645034
im creating a method where a user input has to type A/B to get a return. how do i make my code case insensitive to make it work?
我正在创建一种方法，其中用户输入必须键入 A/B 才能获得回报。我如何使我的代码不区分大小写以使其工作？
String examcode (String code) {
if (code.compareToIgnoreCase("A")) {
EXAM_NAME = "Subject A";
}
else if (code.compareToIgnoreCase("B")) {
EXAM_NAME = "Subject B";
}
else {
EXAM_NAME = "no code";
}
return EXAM_NAME;
}
回答by Mark Peters
Use equalsIgnoreCase(), not compareToIgnoreCase().
使用equalsIgnoreCase()，不是compareToIgnoreCase()。
if (code.equalsIgnoreCase("A")) {
EXAM_NAME = "Subject A";
} //...
If you want to use compareToIgnoreCase()to check equality, you need to compare the result to 0:
如果要用于compareToIgnoreCase()检查相等性，则需要将结果与0：
if (code.compareToIgnoreCase("A") == 0) {
//...
just like any other compareTomethod. But there's no advantage to using it here.
就像任何其他compareTo方法一样。但是在这里使用它没有任何好处。
Edit:
编辑：
An alternative to your entire approach might be to use a case-insensitive map instead. Something like this:
整个方法的替代方法可能是使用不区分大小写的映射。像这样的东西：
Map<String, String> subjects = new TreeMap<String, String>(String.CASE_INSENSITIVE_ORDER);
subjects.put("A", "Subject A");
subjects.put("B", "Subject B");
//...
String subjectName = subjects.get(code);
if ( subjectName == null ) {
subjectName = "no code";
}
Or, you could also use a normal case-sensitive map and just convert all keys to lower case before doing map operations.
或者，您也可以使用普通的区分大小写的映射，并在执行映射操作之前将所有键转换为小写。
回答by Bhesh Gurung
Just use the method -
String.equalsIgnoreCase(java.lang.String)which returns a booleanand does the job for what you are looking for.
只需使用该方法 -
String.equalsIgnoreCase(java.lang.String)它返回 aboolean并完成您正在寻找的工作。
if (code.compareToIgnoreCase("A"))is not valid since compareToIgnoreCasereturns int.
if (code.compareToIgnoreCase("A"))无效，因为compareToIgnoreCase返回int。
回答by Richard Sitze
Reading the javadoc for Stringwould have provided your answer for you. Google would have turned that right up.
阅读String的javadoc 将为您提供答案。谷歌本来可以做到这一点的。
Use
code.equalsIgnoreCase("your string")which returns a boolean value, ORuse
code.compareToIgnoreCase("your string") == 0.compareToIgnoreCasegives you a way to determine the "order" of two strings. Again, enjoy the javadoc.
使用
code.equalsIgnoreCase("your string")它返回一个布尔值，或使用
code.compareToIgnoreCase("your string") == 0.compareToIgnoreCase为您提供了一种确定两个字符串的“顺序”的方法。再次享受 javadoc。
回答by jelies
Use same code but equalsIgnoreCase(String) instead of compareToIgnoreCase(String).
使用相同的代码，但使用 equalsIgnoreCase(String) 而不是 compareToIgnoreCase(String)。
回答by qqilihq
What you want is String#equalsIgnoreCase(String)which returns a boolean.
你想要的是String#equalsIgnoreCase(String)返回一个布尔值。
回答by Frank Thomas
use String.toLowerCase() (or String.toUpperCase()) before comparing.
在比较之前使用 String.toLowerCase()（或 String.toUpperCase()）。
if (code.toLowerCase().equals("a")) {
EXAM_NAME = "Subject A";
}
Note that like all string methods, code.toLowerCase does not change the string stored in 'code', but returns a copy of 'code's value all in lower case.
请注意，与所有字符串方法一样，code.toLowerCase 不会更改存储在“code”中的字符串，而是以小写形式返回“code”值的副本。
