Question

我有以下方法返回一个IList<IGrouping<bool, int>>，我想知道是否可以使用LINQ来做到这一点。（下面我写了测试用例，看看会发生什么，小数（<= 100）应该的布尔值是“是”，大数字（> 100）的布尔值应该是“否”。

public IList<IGrouping<bool, int>> GroupSmallAndBigNumbers(int[] numbers)
        {

        }

[Test]
        public void NumbersSmallerThanOrEqualTo100AndBiggerNumbersCanBeGroupedUsingGroupBy()
        {
            //Arrange
            int[] numbers = { 5, 700, 15, 108, 25, 28, 100 };
            int[] expectedSmallNumbers = { 5, 15, 25, 28, 100};
            int[] expectedBigNumbers = { 700, 108 };

            //Act
            var results = _examples.GroupSmallAndBigNumbers(numbers);

            //Assert
            Assert.That(results.Count, Is.EqualTo(2));
            var smallNumbers = results[0];
            Assert.That(smallNumbers, Is.EquivalentTo(expectedSmallNumbers));
            var bigNumbers = results[1];
            Assert.That(bigNumbers, Is.EquivalentTo(expectedBigNumbers));
        }

Answer 1

您可以通过检查每个数字是否大于100来进行分组。

public IList<IGrouping<bool, int>> GroupSmallAndBigNumbers(int[] numbers)
 => numbers.GroupBy(x => x >= 100).ToList();

Answer 2

我认为Dictionary对您来说会更好（也更容易）。使用它，您可以轻松地执行以下操作：

 ❌  Environment aws://ACCOUNTIDHERE/us-west-2 failed bootstrapping: Error: Need to perform AWS calls for account ACCOUNTIDHERE, but no credentials found. Tried: default credentials.
    at CredentialsCache.getCredentials (/usr/local/lib/node_modules/aws-cdk/lib/api/util/sdk.ts:261:11)
    at CredentialsCache.get (/usr/local/lib/node_modules/aws-cdk/lib/api/util/sdk.ts:223:25)
    at SDK.cloudFormation (/usr/local/lib/node_modules/aws-cdk/lib/api/util/sdk.ts:117:20)
    at Object.deployStack (/usr/local/lib/node_modules/aws-cdk/lib/api/deploy-stack.ts:56:15)
    at Object.bootstrapEnvironment (/usr/local/lib/node_modules/aws-cdk/lib/api/bootstrap-environment.ts:93:10)
    at /usr/local/lib/node_modules/aws-cdk/bin/cdk.ts:270:24
    at async Promise.all (index 1)
Need to perform AWS calls for account ACCOUNTIDHERE, but no credentials found. Tried: default credentials.

是否可以使用LINQ进行分组？

2 个答案: