VB.Net 上的正则表达式只从左到右获取前几个数字 [英] Regex on VB.Net to get only first few numbers from left to right

问题描述

我对正则表达式很陌生，但就我一直在 Google 上闲逛而言，我唯一能做的就是通过正则表达式来解决我的问题.

I am pretty new on regular expressions, but as far as I've been wandering around Google, the only thing I could do to solve my problem is through regex.

我有一组字符串，它们具有以下模式:

I have a collection of strings which have patterns like these:

3 - 橙子，柠檬"
4 - 菠萝，橙子"
12 - 酸橙、草莓"

"3 - Orange, Lemon"
"4 - Pineapple, Orange"
"12 - Lime, Strawberry"

我当前的代码是:

Private Sub cmbKelas_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbKelas.SelectedIndexChanged
        LblID.Text = cmbKelas.Text
End Sub

它为整个字符串提供输出..我想要的是 cmbKelas.Text 将剥离其值，因此每个字符串将变为:

Which gives output to entire string.. what I wanted is that cmbKelas.Text will have its value stripped so each string will changes into:

3"
4"
12"

"3"
"4"
"12"

只有前几个数字.评论、建议或指向正确链接/文章会有所帮助，因为到目前为止我无法找到易于理解的体面教程.

Only the first few numbers. A comment, suggestion, or point to the right links/articles would help because so far I couldn't manage to find a decent tutorials that easy to understand.

推荐答案

如果你想用正则表达式做到这一点，你可以使用这样的东西:

If you want to do this with Regular Expressions you could use something like this:

Dim ResultString As String
ResultString = Regex.Match(SubjectString, "^\d+").Value

其中 SubjectString 将是您要搜索的字符串.

Where SubjectString would be the string you are searching in.

说明(因为您不熟悉正则表达式):

Explanation (since you are new to regex):

• ^ 表示字符串的开头(这就是为什么你不匹配不在开头的数字)
• \d 表示数字 0-9(这是 [0-9] 的缩写形式，它会做同样的事情)
• 和 + 表示+ 之前的字符将至少匹配一次.

• The ^ signifies the beginning of a string (that why you don't match number that are not at the beginning)
• \d signifies a digit 0-9 (it's the short form of [0-9] which would do the same)
• and + means that the character prior to + will be matched at least once.

这样你就可以在字符串的开头匹配 1 到无限个数字.

That way you will match 1 to infinite digits at the beginning of the string.

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