regex - 如何在字符串中的特定符号之前获取字符串

Question

vb.net 中是否有任何方法可以从电子邮件地址获取用户名？

例如，我有一个字符串变量，它由 value 组成tracywilly@gmail.com，这里我需要获取用户名，即tracywilly我的预期输出

Dim email_addr as string
Dim usr as string
email_addr = "tracywilly@gmail.com"

Answer 1

split()您可以使用或 regex在 vb.net中实现此目的

看下面的方法

1.)split()功能：

 Function username(ByVal str As String) As String
        Dim arStr As String()
        arStr = str.Split("@")
        username = arStr(0)
        Return username
    End Function

2.）regex：

Function username_1(ByVal str As String) As String
    username_1 = System.Text.RegularExpressions.Regex.Match(str, "^.*?(?=@)").ToString
    Return username_1
End Function

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它是如何工作的？

Dim email_addr as string
Dim usr as string
email_addr = "tracywilly@gmail.com"
usr = username(email_addr)
usr = username_1(email_addr)

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Live Demo