从vb.net中的可变长度字符串中提取最后10个字符

Question

I have some sentences like below :

i have a river  
he is liar
great
hello miss
there was a river in this area

Now i want to extract last 10 characters and have this result

ve a river
he is liar
great
hello miss
 this area

I have tried to achieve the desired result using this

mystring.Substring(mystring.Length - 10)

The above code works fine for the strings of length higher than 9, but fails for great How to overcome this problem using fewest line of vb.net code?

Answer 1

您需要使用Math.Min限制子字符串，以便它可以从字符串中获取10或尽可能多的子字符串。

mystring.Substring(mystring.Length - Math.Min(10, mystring.Length))

Answer 2

The Strings.Right Method will do what you want.

Dim ss = {"i have a river", "he is liar", "great", "hello miss", "there was a river in this area"}
For Each s In ss
    Console.WriteLine(Strings.Right(s, 10))
Next

Outputs:

ve a river
he is liar
great
hello miss
 this area

I assume that the missing space at the start of the last string was a transcription error in the question.

Answer 3

你可以反转字符串（将其转换为字符数组），从start开始取10个字符，然后将其反转并通过连接数组转换为字符串。

String.Join("", mystring.Reverse().Take(10).Reverse())

Answer 4

Microsoft.VisualBasic.Strings.Right(mystring, 10)

Another simple but efficient solution i found :

mystring.Substring(Math.Max(0, mystring.Length - 10))