如何用dart打印地图?

Question

我知道如何使用foreach()方法打印地图

var x = {1:'One',2:'Two',3:'Three',4:'Four',5:'Five'};
x.foreach((i,j){
print(i);
print(j);
});

和使用正常的for循环

打印地图的其他方法?

Answer 1

您也可以直接打印地图:

void main() {
var x = {1:'One',2:'Two',3:'Three',4:'Four',5:'Five'};
print(x);
}

结果将非常简洁:

{1: One, 2: Two, 3: Three, 4: Four, 5: Five}

您可以在这里找到mapToString的实现。

static String mapToString(Map<Object?, Object?> m) {
// Reuses the list in IterableBase for detecting toString cycles.
if (_isToStringVisiting(m)) {
return '{...}';
}
var result = StringBuffer();
try {
_toStringVisiting.add(m);
result.write('{');
bool first = true;
m.forEach((Object? k, Object? v) {
if (!first) {
result.write(', ');
}
first = false;
result.write(k);
result.write(': ');
result.write(v);
});
result.write('}');
} finally {
assert(identical(_toStringVisiting.last, m));
_toStringVisiting.removeLast();
}
return result.toString();
}