CODEWITHSUNDEEP
dart
Marko
Marko

Reputation: 79

Sum of all values in a map in Dart

I have a Map<String, Map<String, double>> myMap = ... and I would like to sum all the values in the second map. I have managed to do it like this

 double sum = 0;
 myMap.entries.forEach((element) {
 Map<String, double> map = element.value;
 sum += map.entries.map((e) => e.value).toList().fold(0, (a, b) => a + b);
 });

Is it possible to sum it using only one line without .forEach()?

Upvotes: 1

Views: 1007

Answers (3)

user14631430
user14631430

Reputation:

ok, then an another option:

var sum = myMap.values.expand((e) => e.values).fold(0, (a, b) => a + b);

Upvotes: 2

Marko
Marko

Reputation: 79

I've managed to come up with the solution that works and all in one line.

double sum = myMap.values
        .map((e) => e.values)
        .fold(0, (a, b) => a + b.fold(0, (a, b) => a + b));

Upvotes: 0

Joseph Utulu
Joseph Utulu

Reputation: 246

Try this one liner:

num sum = 0;
map.forEach((k, v) => v.forEach((kk, vv) => sum += vv));

Upvotes: 1

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