In Java how does one turn a String into a char or

问题:

Is there a way to turn a char into a String or a String with one letter into a char (like how you can turn an int into a double and a double into an int)? (please link to the relevant documentation if you can).

How do I go about finding something like this that I'm only vaguely aware of in the documentation?

回答1:

char firstLetter = someString.charAt(0);
String oneLetter = String.valueOf(someChar);

You find the documentation by identifying the classes likely to be involved. Here, candidates are java.lang.String and java.lang.Character.

You should start by familiarizing yourself with:

• Primitive wrappers in java.lang
• Java Collection framework in java.util

It also helps to get introduced to the API more slowly through tutorials.

• Manipulating characters in a String

回答2:

String.valueOf('X') will create you a String "X"

"X".charAt(0) will give you the character 'X'

回答3:

As no one has mentioned, another way to create a String out of a single char:

String s = Character.toString('X');

Returns a String object representing the specified char. The result is a string of length 1 consisting solely of the specified char.

回答4:

String someString = "" + c;
char c = someString.charAt(0);

回答5:

String g = "line";
//string to char
char c = g.charAt(0);
char[] c_arr = g.toCharArray();
//char to string
char[] charArray = {'a', 'b', 'c'};
String str = String.valueOf(charArray);
//(or iterate the charArray and append each character to str -> str+=charArray[i])

//or String s= new String(chararray);

回答6:

In order to convert string to char

 String str = "abcd";
char arr [] = new char[len]; // len is the length of the array
arr = str.toCharArray();

回答7:

I like to do something like this:

String oneLetter = "" + someChar;