Question

我有这段代码，想知道相同的lambda表达式是什么。实际上，我尝试了相同的高级教程，但仍然无法从注释行开始找出以下代码的lambda表达式。

IDictionary<string, GitItem> mappedPathToGitItems = new Dictionary<string, GitItem>();

mappedPathToGitItems = clientWrapper.GetFilePathToGitItems(
        gitLatestCommit, versionDescriptor, mappedPath, maxBatchSize);

List<string> filepaths = new List<string>();

// Lambda expression starts from here
// filepaths = {Lambda expression of the below code.}
foreach(KeyValuePair<string, GitItem> entry in mappedPathToGitItems)
{
    string item = entry.Key;
    GitItem gitItem = entry.Value;

    if(gitItem != null)
    {
        filepaths.Add(item);
    }
}
// Ends here

Answer 1

List<string> filepaths = mappedPathToGitItems
    .Where(kvp => kvp.Value != null)
    .Select(kvp => kvp.Key)
    .ToList();

Answer 2

当您说“ lambda表达式等效”时，我认为您的意思是通过LINQ：

return Column(
    children: <Widget>[
    Text('Hellow'),
  ListView(
  padding: const EdgeInsets.only(top: 20.0),
  children: snapshot.map((data) => _buildListItem(context, data)).toList(),
)]);

相当于代码的lambda表达式是什么

2 个答案: