问题描述
我有一个项目，我通过首字母查询用户:
I have a project where I query users by first letter:
repository.GetAll().Where(q => q.BrukerIdent.StartsWith(letter.ToString())).ToList();
..where repository.GetAll() 返回一个 IQueryable，BrukerIdent 是一个包含用户名的字符串，letter 是一个传入的字符值.这很好用，除了我还想获得以数字开头的用户.而且我不想按单独的数字排序.
..where repository.GetAll() returns an IQueryable<Bruker>, BrukerIdent is a string that contains the username, and letter is a char-value coming in. This works perfectly, except that I also want to get users that starts with digits. And I don't want to sort by separate digits.
我的脑海里呼喊着 StartsWith("d") 但据我所知，它不是这样工作的.我也想过做一个 10 路 OR 子句，但这看起来像意大利面条，我不确定效率.
My mind yells for a StartsWith("d") but as far as I have found out it doesn't work this way. I have also thought of doing a 10-way OR clause, but that would look like spaghetti, and I'm not sure of the efficiency.
有没有什么正确"的方法可以做到这一点?
Is there any "right" way to do it like this?
推荐答案
repository.GetAll().Where(q => Char.IsNumber(q.BrukerIdent[0]))
MSDN
var numbers = Enumerable
.Range(0, 10)
.Select(i => i.ToString(CultureInfo.InvariantCulture));
// var numbers = new[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 );
// var numbers = HashSet<int> { ... };
var q = from b in repository.GetAll()
where numbers.Contains(b.BrukerIdent.FirstOrDefault())) //[0]
select b;
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