[Dart]Find and Replace Strings

问题

noob here:D I'm using flutter for this app and i'm having trouble with the app's logic. Any help is much appreciated.

App goal: Decode(replace) all input abbreviation to words by: -User inputs text via text box -App looks for any abbreviations(several) and replaces the abbreviation only with text.

I was able to do it will a few abbreviation but with my case all abbreviation should be in the input text or it wouldn't work or the second index wont work. I tried several ways which didn't work, I'm using 2 list for the abv and corresponding text.

Here is the code.

List<String> coded = ["GM", "HOT", "YAH"]; //ABV list
List<String> decoded = ["Gmail", "Hotmail", "Yahoo"]; //corresponding list 
Map<String, String> map = new Map.fromIterables(coded, decoded);

String txt = "HOT was the best until GM took over"; //input text

void main() {
  if ((txt.contains(coded[0]))) { //GM
    String result = txt.replaceAll(coded[0], decoded[0]); //Replace with Gmail

    print(result);
  }
  else if ((txt.contains(coded[0])) && (txt.contains(coded[1]))) {
    String result = (txt.replaceAll(coded[0], decoded[0]));
    (txt.replaceAll(coded[1], decoded[1]));

    print(result);
  }
  else if ((txt.contains(coded[0])) && (txt.contains(coded[1])) && (txt.contains(coded[2]))) {
    String result = txt.replaceAll(coded[0], decoded[0]);
    txt.replaceAll(coded[1], decoded[1]);
    txt.replaceAll(coded[2], decoded[2]);

    print(result);
  }
  else {
    print(txt);
  }
}

I'm sorry if this seems so simple, still learning.

Thanks

回答1:

What you want can be done quite easily with fold:

List<String> coded = ["GM", "HOT", "YAH"]; //ABV list
List<String> decoded = ["Gmail", "Hotmail", "Yahoo"]; //corresponding list 
Map<String, String> map = new Map.fromIterables(coded, decoded);

String txt = "HOT was the best until GM took over"; //input text

void main() {
  final result = map.entries
    .fold(txt, (prev, e) => prev.replaceAll(e.key, e.value));
  print(result);
}

Basically you will iterate on map entries (pairs of key/value). fold takes an initial value (txt in your case) and a function to update the previous value with the current element that is iterated. After each iteration the result has replaced all ABV.

来源：https://stackoverflow.com/questions/52615539/dartfind-and-replace-strings

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replace

dart

find