Replace instances of character in a string with array values

Question

How would i go about replacing all instances of a character or string within a string with values from an array?

For example

String testString = "The ? ? was ? his ?";

String[] values = new String[]{"brown", "dog", "eating", "food"};

String needle = "?";

String result = replaceNeedlesWithValues(testString,needle,values);

//result = "The brown dog was eating his food";

method signature

public String replaceNeedlesWithValues(String subject, String needle, String[] values){
    //code
    return result;
}

I'd give this a shot stackoverflow.com/questions/3695230/… — Dan Drews
– Dan Drews, Commented Jun 7, 2013 at 3:56
nope. not homework. I could attempt to write something that uses a lot of substrings but i know there's a more efficient way to go about doing this. — David
– David, Commented Jun 7, 2013 at 3:59

C. K. Young · Accepted Answer · 2013-06-07 04:09:20Z

9

By using String.format:

public static String replaceNeedlesWithValues(String subject, String needle, String[] values) {
    return String.format(subject.replace("%", "%%")
                                .replace(needle, "%s"),
                         values);
}

:-)

Of course, you'll probably just want to work with String.format directly:

String.format("The %s %s was %s his %s", "brown", "dog", "eating", "food");
// => "The brown dog was eating his food"

edited Jun 7, 2013 at 4:09

answered Jun 7, 2013 at 3:55

C. K. Young

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8 Comments

Cat Over a year ago

This is clever... I like this.

David Over a year ago

perfect. thank you. I knew there was a better way than finding the positions of the needle and then using substrings.

C. K. Young Over a year ago

@David Of course, but this also illustrates that you'd be far better off using String.format directly in your code (use %s as your placeholders rather than ?). :-)

David Over a year ago

could you edit your answer to show that? i've not worked with replace() or format() before

C. K. Young Over a year ago

@David Sure thing. (The replace was simply to replace your ? with %s; general usage would not require using replace.)

|

Edwin Dalorzo · Accepted Answer · 2013-06-07 04:07:03Z

1

If your string contains patterns that need to be replaced, you can use the appendReplacement method in the Matcher class.

For example:

StringBuffer sb = new StringBuffer();
String[] tokens = {"first","plane tickets","friends"};
String text = "This is my 1 opportunity to buy 2 for my 3";
Pattern p = Pattern.compile("\\d");
Matcher m = p.matcher(text);
for(int i=0; m.find(); i++) {
    m.appendReplacement(sb, tokens[i]);
}
m.appendTail(sb);

answered Jun 7, 2013 at 4:07

Edwin Dalorzo

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