How do I apply the for-each loop to every character in a String?

java string loops foreach char
Lyndon White picture Lyndon White · Mar 16, 2010 · Viewed 450.4k times · Source

So I want to iterate for each character in a string.

So I thought:

for (char c : "xyz")

but I get a compiler error:

MyClass.java:20: foreach not applicable to expression type

How can I do this?

Answer

polygenelubricants picture polygenelubricants · Mar 16, 2010

The easiest way to for-each every char in a String is to use toCharArray():

for (char ch: "xyz".toCharArray()) {
}

This gives you the conciseness of for-each construct, but unfortunately String (which is immutable) must perform a defensive copy to generate the char[] (which is mutable), so there is some cost penalty.

From the documentation:

[toCharArray() returns] a newly allocated character array whose length is the length of this string and whose contents are initialized to contain the character sequence represented by this string.

There are more verbose ways of iterating over characters in an array (regular for loop, CharacterIterator, etc) but if you're willing to pay the cost toCharArray() for-each is the most concise.

Related questions

Write a method to print out a string "Name" multiple times

I am answering a question for an Intro to Programming class and cannot - after reading through my notes, Big Java book, and looking online - find out where to begin. It seems as though it should be very simple, …

Read More
How do I convert a String to an int in Java?

How can I convert a String to an int in Java? My String contains only numbers, and I want to return the number it represents. For example, given the string "1234" the result should be the number 1234.

Read More
How to split a string in Java

I have a string, "004-034556", that I want to split into two strings: string1="004"; string2="034556"; That means the first string will contain the characters before '-', and the second string will contain the characters after '-'. I also want to …

Read More