CODEWITHSUNDEEP
javalambdaforeachjava-streamindexof
Pavan
Pavan

Reputation: 337

How to do substring in some elements of string list using lambda

Below is my list of String.

["sunday", "monday", "tuesday", "wednesday", "thurs", "fri", "satur"]

I want to do remove "day" from the elements, if it is ending with "day".

Expected Output in the list:

["sun", "mon", "tues", "wednes", "thurs", "fri", "satur"]

How to do this using Lambda?

I have tried the below code, but was unable to assign the value to the list:

daysList.stream().forEach(s -> {
    if (s.endsWith("day")) {
        s = s.substring(0, s.indexOf("day"));
    }
});

Upvotes: 8

Views: 20943

Answers (4)

Rintu
Rintu

Reputation: 13

Sub String with decimal points sorting .

String arr[]= {"2.4","4.2","3.1","5.7","3.0","2.01","7.06","6.003"};

List newList =Arrays.asList(arr); newList.stream().map(n -> n.substring(n.indexOf('.')) ).collect(Collectors.toList()).stream().sorted().forEach(n -> System.out.println(n));;

Upvotes: 1

TNT
TNT

Reputation: 2920

Iterating over the stream using forEach won't work; you need to map each of the elements you modified to a new stream using map. Then you can collect the results back to your list.

daysList = daysList.stream()
        .map(s -> s.endsWith("day") ? s.substring(0, s.length()-3) : s)
        .collect(Collectors.toList());

Upvotes: 8

VGR
VGR

Reputation: 44318

Most of the answers here make use of a Stream, but you should not be using a Stream at all:

daysList.replaceAll(s -> s.replaceFirst("day$", ""));

Upvotes: 16

Tahar Bakir
Tahar Bakir

Reputation: 716

List<String> daysList = Arrays.asList("sunday", "monday", 
                                      "tuesday", "wednesday",
                                       "fri", "satur" 
                                      );


List<String> res = daysList.stream()
                            .map(s -> s.replace("day",""))
                            .collect(Collectors.toList());

Upvotes: 1

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