Question 259929 in Flutter Question posted in
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Flutter – How to replace with the same character in list<String>

i have list string like this :
List<String> alphabet = [a,b,c];

then i add same string like : alphabet.add(a);

the result is [a,b,c,a]

the question is, How do I make sure the values ​​in the string list
remain the same [a,b,c] because the value a already exists in the string list

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2

Answers


  1. 0

    The easiest way is to check if the character is already contained before adding it.

    if(!alphabet.contains(newChar)){
    alphabet.add(newChar);
}
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  2. 0

    Use Set (https://api.dart.dev/stable/3.1.3/dart-core/Set-class.html):

    Set<String> alphabet = Set();
alphabet.add("a");
alphabet.add("a"); // Won't be added
alphabet.add("b");

print(alphabet);

// Result: {a, b}

    Sets are like lists but automatically ignores duplicates, the best (and suggested) solution for your needs.

    Also, you can convert it to List using alphabet.toList();

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