How do I set a string variable to a string contained in another variable

Question

For example, I have a string variable line

(line.contains("for") || line.contains("def") || line.contains("if")    || line.contains("while") || line.contains("else") || line.contains("elif")

and I want to set a new string variable keyword to the keyword in this conditional statement, how would be able to do this, like keyword = keyword in line.

@pmcarpan i dont think it is a duplicate, he is asking after the condition he wants to assign to variable that makes true the condition — The Scientific Method
– The Scientific Method, Commented Oct 2, 2018 at 12:48
line.contains("if") || line.contains("elif") is redundant; if the line does not contain "if", then it won't contain "elif". — Jacob G.
– Jacob G., Commented Oct 2, 2018 at 12:50
For the record: if you really try to parse some sort of language, then contains() is wrong. Then you have to use a parser, to correctly identify and process the different elements of your input. What if the line is if a == "def"or something like that? — GhostCat
– GhostCat, Commented Oct 2, 2018 at 12:57

Benoit · Accepted Answer · 2018-10-02 13:09:32Z

4

Stream provide a simple and elegant solution in this case:

    String keyword = Stream.of("elif", "for", "def", "if", "while", "else")
            .filter(line::contains)
            .findFirst()
            .orElse("no-keyword-found");

Note: "elif" must be placed before "if"

edited Oct 2, 2018 at 13:09

answered Oct 2, 2018 at 12:54

Benoit

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1 Comment

walen Over a year ago

"I removed "elif" keyword because it will never be returned." → It will, as long as it comes before if.

Michael · Accepted Answer · 2018-10-02 12:56:29Z

0

Why not something like this?

public static Optional<String> getFirstMatch(String string, String... subStrings)
{
    return Arrays.stream(subStrings).filter(string::contains).findFirst();
}

Sample usage:

Optional<String> match = getFirstMatch("myInput", "my", "Input");
if (match.isPresent())
{
    String foo = match.get();
    //...
}

answered Oct 2, 2018 at 12:56

Michael

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Comments

The Scientific Method · Accepted Answer · 2018-10-02 13:43:22Z

0

alternative here:

List<String> keywords = new LinkedList<String>;
keywords.add("for");  // put your keywords in a list
keywords.add("def");
keywords.add("if");
keywords.add("else");
String strword;
for(keyword:keywords){
 if(line.contains(keyword)){
    String strword = keyword;
 }    
}

edited Oct 2, 2018 at 13:43

answered Oct 2, 2018 at 12:54

The Scientific Method

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