'Check if one List<String> contains specific string from another list

I have a List<String> emails containing emails, and another List<String> keywords for containing keywords. For each i-th value from keywords, there should be a string on i-th index that contains this value.

So, if emails.get(0) == "quick brown fox", then keywords.get(0) == "fox".

if emails.get(5) == "foo bar", then keywords.get(5) == "foo".

How can I check (other than for loop) that each email contains a keyword?

javaarraylistcollectionsjava-stream


Solution 1:[1]

First, it may be needed to check the size of both lists, then to compare corresponding list items, IntStream should be used:

public static boolean allKeywordsFound(List<String> emails, List<String> keywords) {
    return emails.size() == keywords.size() &&
        IntStream.range(0, emails.size())
            .allMatch(i -> emails.get(i).contains(keywords.get(i)));
}

Solution 2:[2]

I see that others correctly answered your question but here's my take on the issue. I presume you want the emails to be checked in order so here's a piece of code that uses Stream API instead of a for loop, I also put together the emails list and the result into a Map since you didn't specify whether you want the resulting boolean value to be for all the emails together or if you want a boolean value for each email containing the same-position keyword:

//mock data initialization
List<String> emails = new ArrayList<>();
List<String> keywords = new ArrayList<>();

//mock data initialization
emails.add("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua");
emails.add("eu lobortis elementum nibh tellus molestie nunc non blandit massa enim nec dui nunc mattis enim ut tellus elementum sagittis");
emails.add("Dignissim suspendisse in est ante in nibh mauris");

//mock data initialization
keywords.add("consectetur");
keywords.add("Foo");
keywords.add("Dignissim");

//initialized a list to contain whether a keyword exists for each email
List<Boolean> exists = new ArrayList<>();

//loaded it with boolean values (the exists List has the same order as the emails list)
emails.forEach(email -> exists.add(email
            .contains(keywords
                    .get(emails
                            .indexOf(email)))));

//since I don't know what you wanna do with the result, I decided to just put them together in a Map
//with the email string as the key and the existence variable as a value
LinkedHashMap mapOfTruth = new LinkedHashMap();
emails.forEach(email -> mapOfTruth.put(email, exists.get(emails.indexOf(email))));

Output

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua = true
eu lobortis elementum nibh tellus molestie nunc non blandit massa enim nec dui nunc mattis enim ut tellus elementum sagittis = false
Dignissim suspendisse in est ante in nibh mauris = true

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 Amine

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