Flutter/Dart: Split string by first occurrence

You were never going to be able to do all of that, including trimming whitespace, with the split command. You will have to do it yourself. Here's one way:

String s = "date   :   '2019:04:01'";
int idx = s.indexOf(":");
List parts = [s.substring(0,idx).trim(), s.substring(idx+1).trim()];

You can split the string, skip the first item of the list created and re-join them to a string.

In your case it would be something like:

var str = "date: '2019:04:01'";
var parts = str.split(':');
var prefix = parts[0].trim();                 // prefix: "date"
var date = parts.sublist(1).join(':').trim(); // date: "'2019:04:01'"

The trim methods remove any unneccessary whitespaces around the first colon.

Just use the split method on the string. It accepts a delimiter/separator/pattern to split the text by. It returns a list of values separated by the provided delimiter/separator/pattern.

Usage:

const str = 'date: 2019:04:01';
final values = string.split(': '); // Notice the whitespace after colon

Output:

Inspired by python, I've wrote this utility function to support string split with an optionally maximum number of splits. Usage:

split("a=b=c", "="); // ["a", "b", "c"]
split("a=b=c", "=", max: 1); // ["a", "b=c"]
split("",""); // [""] (edge case where separator is empty)
split("a=", "="); // ["a", ""]
split("=", "="); // ["", ""]
split("date: '2019:04:01'", ":", max: 1) // ["date", " '2019:04:01'"] (as asked in question)

Define this function in your code:

List<String> split(String string, String separator, {int max = 0}) {
  var result = List<String>();

  if (separator.isEmpty) {
    result.add(string);
    return result;
  }

  while (true) {
    var index = string.indexOf(separator, 0);
    if (index == -1 || (max > 0 && result.length >= max)) {
      result.add(string);
      break;
    }

    result.add(string.substring(0, index));
    string = string.substring(index + separator.length);
  }

  return result;
}

Online demo: https://dartpad.dev/e9a5a8a5ff803092c76a26d6721bfaf4

I found that very simple by removing the first item and "join" the rest of the List

String date = "date:'2019:04:01'";
List<String> dateParts = date.split(":");
List<String> wantedParts = [dateParts.removeAt(0),dateParts.join(":")];

Use RegExp

string.split(RegExp(r":\s*(?=')"));

1. Note the use of a raw string (a string prefixed with r)
2. \s* matches zero or more whitespace character
3. (?=') matches ' without including itself

You can use extensions and use this one for separating text for the RichText/TextSpan use cases:

extension StringExtension on String {
 List<String> controlledSplit(
  String separator, {
  int max = 1,
  bool includeSeparator = false,
  }) {
   String string = this;
   List<String> result = [];

   if (separator.isEmpty) {
     result.add(string);
     return result;
   }

   while (true) {
     var index = string.indexOf(separator, 0);
     print(index);
     if (index == -1 || (max > 0 && result.length >= max)) {
       result.add(string);
       break;
     }

     result.add(string.substring(0, index));
     if (includeSeparator) {
       result.add(separator);
     }
     string = string.substring(index + separator.length);
   }

   return result;
 }
}

Then you can just reference this as a method for any string through that extension:

void main() {
 String mainString = 'Here was john and john was here';
 print(mainString.controlledSplit('john', max:1, includeSeparator:true));
}

Just convert list to string and search

  productModel.tagsList.toString().contains(filterText.toLowerCase())