Ignoring upper case and lower case in Java

问题

I want to know how to make whatever the user inputs to ignore case in my method:

public static void findPatient() {
    if (myPatientList.getNumPatients() == 0) {
        System.out.println("No patient information is stored.");
    }
    else {
        System.out.print("Enter part of the patient name: ");
        String name = sc.next();
        sc.nextLine();
        System.out.print(myPatientList.showPatients(name));
    }
}

回答1:

You have to use the String method .toLowerCase() or .toUpperCase() on both the input and the string you are trying to match it with.

Example:

public static void findPatient() {
    System.out.print("Enter part of the patient name: ");
    String name = sc.nextLine();

    System.out.print(myPatientList.showPatients(name));
}

//the other class
ArrayList<String> patientList;

public void showPatients(String name) {
    boolean match = false;

    for(String matchingname : patientList) {
        if (matchingname.toLowerCase().contains(name.toLowerCase())) {
            match = true;
        }
    }
}

回答2:

Use String#toLowerCase() or String#equalsIgnoreCase() methods

Some examples:

    String abc    = "Abc".toLowerCase();
    boolean isAbc = "Abc".equalsIgnoreCase("ABC");

回答3:

The .equalsIgnoreCase() method should help with that.

回答4:

use toUpperCase() or toLowerCase() method of String class.

回答5:

You ignore case when you treat the data, not when you retrieve/store it. If you want to store everything in lowercase use String#toLowerCase, in uppercase use String#toUpperCase.

Then when you have to actually treat it, you may use out of the bow methods, like String#equalsIgnoreCase(java.lang.String). If nothing exists in the Java API that fulfill your needs, then you'll have to write your own logic.