CODEWITHSUNDEEP
javaregex
Vitaliy Tretyakov
Vitaliy Tretyakov

Reputation: 179

Collections.replaceAll(List<T> list, T oldVal, T newVal) does not work with regex properly, Java

I'm solving the problem where I must find the longest string in the list and replace all other list items with that string:

The longest string in the list

Inside the given method you should:

1. find the longest string in the list
2. replace all list items with the found string

When I use regular expression "\\w+" the method does not work:

Collections.replaceAll(list, "\\w+", longestString);

When I replace the specific words by specifying them in a method argument - all works properly, e.g.:

Collections.replaceAll(list, "word", longestString);

Why is that? Where is my error?

Upvotes: 1

Views: 328

Answers (1)

Mushif Ali Nawaz
Mushif Ali Nawaz

Reputation: 3866

Collections.replaceAll method does not support Regex. Probably you should use List.replaceAll method: 

list.replaceAll(e -> longestString);

Here is the working example:

// Dummy Values
List<String> list = new ArrayList<>();
list.add("Hey");
list.add("World");
list.add("Bye");
String longestString = "World";

// Replacing every word with `longestString`
list.replaceAll(e -> longestString);

// Printing
System.out.println(list);

Output:

[World, World, World]

Upvotes: 1

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