Dart syntax - ${},r,List,Map, ... & ...?

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☝${expression}

☝raw
☝list 也就是所謂的array
☝... 與  ...?  之插入功能
spread operator (...) and the null-aware spread operator (...?), which provide a concise way to insert multiple elements into a collection.
☝list 之for / if之應用

☝Map 字典-有索引值的陣列








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