Replacing contents inside curly braces (for e.g. {1}) with something else

Question

I have a string as follows

Hey {1}, you are {2}.

Here 1 and 2 are key whose value will be added dynamically.

Now I need to replace {1} with the value that 1 represents and then I need to replace {2} with the value that 2 represents in the sentence above.

How do I do it?

I know what split function of a string does and I know very well that with that function I can do what I want but I am looking for something better.

Note: I don't know what these keys are in advance. I need to retrieve the keys as well. And then according to the keys I need to replace the values in the string.

@Smrita you want to replace `{1}` and `{2}` from your string and there are only two values in your string that you want to replace not more than 2 is that right.. — amit bhardwaj, Jun 17 '14 at 06:01
So it means your string also look like this `Hey {1} , you are {2} and you can {3} with {4}` and so on.....and you have to replace all the values in the braces — amit bhardwaj, Jun 17 '14 at 06:09
From the comments you're leaving @Smrita, I'm getting the impression that the keys could be anything. Like {key} for example. Is that correct? — Dan Temple, Jun 17 '14 at 06:12
@Smrita and your key in string is always integer or it could be anything — amit bhardwaj, Jun 17 '14 at 06:14
I have given a solution considering you use a hashmap (and without checking any exceptions). You need to provide more information.. — TheLostMind, Jun 17 '14 at 06:15
@DanTemple and Amit keys will integers and they will be inside curley braces {}. — Smrita, Jun 17 '14 at 06:16
@Smrita: From where are you getting values to be replaced for `1`, `2`, `3` etc? — anubhava, Jun 17 '14 at 06:16
ok but how are you keeping those keys and values in your Java code? Are you using a `Map`? — anubhava, Jun 17 '14 at 06:21
In that case did you take a look at answer from @TheLostMind? — anubhava, Jun 17 '14 at 06:23

score 13 · Answer 1 · edited Mar 27 '17 at 17:41

13

You can use MessageFormat from java.text.MessageFormat. Message Format has some example on how it can be used in this type of scenario

edited Mar 27 '17 at 17:41

Taylor

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answered Jun 17 '14 at 06:34

Pranav Maniar

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score 7 · Accepted Answer · edited May 23 '17 at 12:32

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Thanks to https://stackoverflow.com/users/548225/anubhava for this one.. :). You could do something like this:

public static void main(String[] args) {
    String s = "Hey {1}, you are {2}.";
    HashMap<Integer, String> hm = new HashMap();
    hm.put(1, "one");
    hm.put(2, "two");
    Pattern p = Pattern.compile("(\\{\\d+\\})");
    Matcher m = p.matcher(s);
    while (m.find()) {
        System.out.println(m.group());
        String val1 = m.group().replace("{", "").replace("}", "");
        System.out.println(val1);
        s = (s.replace(m.group(), hm.get(Integer.parseInt(val1))));
        System.out.println(s);
    }

}

Output:

Hey one, you are two.

edited May 23 '17 at 12:32

Community

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answered Jun 17 '14 at 06:05

TheLostMind

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Thank you It works:). TheLostMind rocks:) – Smrita Jun 17 '14 at 06:32
@Smrita - Good luck trying to modify it for more than 2 values :P – TheLostMind Jun 17 '14 at 06:33
This idea is fine but matching and replacement should be done in a `while (m.find()) {...}` loop using a simple regex `\\{(\\d+)\\}` – anubhava Jun 17 '14 at 06:37
@anubhava - yes.. I agree.. I simply complicated the problem.. and was in a hurry to post the solution :P – TheLostMind Jun 17 '14 at 06:41
@Smrita - Use the updated answer. It is better than the earlier one :) – TheLostMind Jun 17 '14 at 06:52
Nice, but maybe not very efficient – Stefan Reich Jun 12 '17 at 17:17

score 4 · Answer 3 · edited Jun 17 '14 at 06:26

4

Try using String.format():

String x = String.format("Hi %s, you are %s\n", str1, str2);

If you have already a string "Hey {1}, you are {2}." you can use regular expressions to replace {1} and {2} with %s.

String template = "Hey {1}, you are {2}.";
String x = String.format(template.replaceAll("\\{\\d\\}", "%s"), "Name", "Surname");

edited Jun 17 '14 at 06:26

Amal Murali

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answered Jun 17 '14 at 05:43

Pablo Francisco Pérez Hidalgo

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I am afraid that I cannot use it! – Smrita Jun 17 '14 at 05:45
@Smrita can't you use format? – Pablo Francisco Pérez Hidalgo Jun 17 '14 at 05:50

score 4 · Answer 4 · answered Jun 17 '14 at 06:34

Try this i think this will work from what i understand from your question

public static void main(String[] args) {
       String str = "Hey {1} your {2} is {3}  clear to {4}  ";
       Map<Integer,String> map = new LinkedHashMap<Integer,String>();
       map.put(1, "Smrita");
       map.put(2, "question");
       map.put(3, "not");
       map.put(4, "anyone");
       while(str.contains("{")){
           Integer i = Integer.parseInt(str.substring(str.indexOf("{")+1, str.indexOf("{")+2));
           str = str.replace("{"+i+"}", map.get(i));

       }
        System.out.println(str);
    }

the output is

Hey Smrita your question is not clear to anyone

aah.. Some of us always tend to ignore the beauty of simplicity. :). +1 — TheLostMind, Jun 17 '14 at 06:36

score 0 · Answer 5 · edited Jun 17 '14 at 06:28

0

Try this:

String str = "Hey {1}, you are {2}.";
str = str.replaceFirst("\\{.*?\\}", "Matt");

Output:

Hey Matt, you are {2}.

The above code will replace the first instance of {1}. If you call this sequence in a loop replacing with the key values from your code, it'll replace all strings within {...} in the order mentioned in the given string.

edited Jun 17 '14 at 06:28

Amal Murali

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answered Jun 17 '14 at 06:20

Anoop George

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Replacing contents inside curly braces (for e.g. {1}) with something else

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