循环通过VB.NET中的字符串中的字符 [英] Looping through characters in a string in VB.NET
问题描述
我正忙于处理过去的考试文件,以准备Visual Basic考试。我需要帮助下面的问题,我被困住。
I'm busy working on past exam papers in preparation for a Visual Basic exam. I need help with the following question which I'm stuck with.
编写函数过程来计算字符e,f和g出现在字符串中的次数
Write a function procedure to calculate the number of times the characters "e", "f" and "g" appears in a string
我试着写出伪代码,并得出以下结果。
I tried to write the psuedo code and came up with the following.
Loop through each individual character in the string
If the character = "e","f" or "g" add 1 to number of characters
Exit loop
Display total in messagebox
如何循环字符串中的单个字符code> for loop)和如何计算特定字符出现在字符串中的次数?
How do I loop through individual characters in a string (using a for
loop) and how do I count the number of times a specific character appears in a string?
推荐答案
答案很大程度上取决于你在课程中学到的内容,以及你应该使用哪些函数。
The answer greatly depends on what you’ve already learned in your course work and which functions you are supposed to use.
循环字符串中的字符就像这样:
But in general, looping over the characters in a string is as easy as this:
Dim s As String = "test"
For Each c As Char in s
' Count c
Next
对于计数,对于每个字符只需要单独的计数器变量( eCount As Integer
等),并在 c
等于该字符 - 显然,一旦增加要计数的字符数,该方法就不会很好地缩放。这可以通过维护相关字符的字典来解决,但我猜测这对你的练习来说太先进了。
As for counting, simply have separate counter variables (eCount As Integer
etc.) for each character and increment them when c
equals that character – obviously that approach doesn’t scale well once you increase the number of characters to count. This can be solved by maintaining a dictionary of the relevant characters but I’m guessing that this is too advanced for your exercise.
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