C# 语法 - 通过逗号将字符串拆分为数组、转换为泛型列表和逆序
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C# Syntax - Split String into Array by Comma, Convert To Generic List, and Reverse Order
提问by BuddyJoe
What is the correct syntax for this:
什么是正确的语法：
IList<string> names = "Tom,Scott,Bob".Split(',').ToList<string>().Reverse();
What am I messing up? What does TSource mean?
我在捣乱什么？TSource 是什么意思？
采纳答案by Jon Skeet
The problem is that you're calling List<T>.Reverse()which returns void.
问题是您正在调用List<T>.Reverse()which 返回void.
You could either do:
你可以这样做：
List<string> names = "Tom,Scott,Bob".Split(',').ToList<string>();
names.Reverse();
or:
或者：
IList<string> names = "Tom,Scott,Bob".Split(',').Reverse().ToList<string>();
The latter is more expensive, as reversing an arbitrary IEnumerable<T>involves buffering all of the data and then yielding it all - whereas List<T>can do all the reversing "in-place". (The difference here is that it's calling the Enumerable.Reverse<T>()extension method, instead of the List<T>.Reverse()instance method.)
后者更昂贵，因为反转任意IEnumerable<T>数据涉及缓冲所有数据然后全部产生 - 而List<T>可以“就地”完成所有反转。（这里的区别在于它调用的是Enumerable.Reverse<T>()扩展方法，而不是List<T>.Reverse()实例方法。）
More efficient yet, you could use:
更高效，您可以使用：
string[] namesArray = "Tom,Scott,Bob".Split(',');
List<string> namesList = new List<string>(namesArray.Length);
namesList.AddRange(namesArray);
namesList.Reverse();
This avoids creating any buffers of an inappropriate size - at the cost of taking four statements where one will do... As ever, weigh up readability against performance in the real use case.
这避免了创建任何大小不合适的缓冲区 - 代价是在一个人可以做的地方执行四个语句......一如既往，在实际用例中权衡可读性与性能。
回答by Yona
Try this:
尝试这个：
List<string> names = new List<string>("Tom,Scott,Bob".Split(','));
names.Reverse();
回答by Rune Grimstad
List<string> names = "Tom,Scott,Bob".Split(',').Reverse().ToList();
This one works.
这个有效。
回答by JaredPar
What your missing here is that .Reverse() is a void method. It's not possible to assign the result of .Reverse() to a variable. You can however alter the order to use Enumerable.Reverse() and get your result
你在这里缺少的是 .Reverse() 是一个 void 方法。无法将 .Reverse() 的结果分配给变量。但是，您可以更改顺序以使用 Enumerable.Reverse() 并获得结果
var x = "Tom,Scott,Bob".Split(',').Reverse().ToList<string>()
The difference is that Enumerable.Reverse() returns an IEnumerable<T> instead of being void return
不同之处在于 Enumerable.Reverse() 返回一个 IEnumerable<T> 而不是 void return
回答by Des Horsley
I realize that this question is quite old, but I had a similar problem, except my string had spaces included in it. For those that need to know how to separate a string with more than just commas:
我意识到这个问题已经很老了，但我遇到了类似的问题，只是我的字符串中包含空格。对于那些需要知道如何用多个逗号分隔字符串的人：
string str = "Tom, Scott, Bob";
IList<string> names = str.Split(new string[] {","," "},
StringSplitOptions.RemoveEmptyEntries);
The StringSplitOptions removes the records that would only be a space char...
StringSplitOptions 删除只会是空格字符的记录...
回答by ablaze
If you are trying to
如果你想
- Use multiple delimiters
- Filter any empty strings
- Trim leading/trailing spaces
- 使用多个分隔符
- 过滤任何空字符串
- 修剪前导/尾随空格
following should work:
以下应该工作：
string str = "Tom Cruise, Scott, ,Bob | at";
IEnumerable<string> names = str
.Split(new char[]{',', '|'})
.Where(x=>x!=null && x.Trim().Length > 0)
.Select(x=>x.Trim());
Output
输出
- Tom
- Cruise
- Scott
- Bob
- at
- 汤姆
- 巡航
- 斯科特
- 鲍勃
- 在
Now you can obviously reverse the order as others suggested.
现在您显然可以按照其他人的建议颠倒顺序。
