问题
I want to know if there is a way to read a text file that lets say has content like so:
Store - 001P Owner - Greg Price - 45000 Employees - 30 Store - 002 Owner- Jen Price - 34400
Now lets say I only want to work with the store information in the block where the store number contains a P. Is there a way to read the text file to check for the P after the delimiter, and then skip to the next instance of "store" in the text file? I tried to find which function is best as in different languages you can GoTo function, but I cannot find anything on this.
This is a snippet of my current code:
Dim columnV As New Dictionary(Of String, Integer)
Dim descriptionV As String
Dim quantityV As Integer
For Each totalLine As String In MyData
descriptionV = Split(totalLine, "-")(0)
quantityV = Split(totalLine, "-")(1)
If columnV.ContainsKey(descriptionV) Then
columnV(descriptionV) = colSums(descriptionV) + quantityV
Else
columnV.Add(descriptionV, quantityV)
End If
'Next
回答1:
Ok, if I read this correct, you only want to worry about and process stores that end in a "P". Did I get that right?
and your data is like this then:
Store - 001P \n Owner - Greg \n Price - 45000 \n Employees - 30 \n
Store - 002\n Owner- Jen \n Price - 34400 \n
So in code we could go:
dim store as string
dim Owner as string
dim Price as decimal
dim employees as integer
' your code to read the data
now we have the process loop
For Each totalLine As String In MyData
store = trim(split(split(totalLine,"\n)(0),"-")(1))
Owner = trim(split(split(totalLine,"\n)(1),"-")(1))
Price = trim(split(split(totalLine,"\n")(3),"-")(1))
Employees = trim(split(split(totalLine,"\n")(4),"-")(1))
if strings.right(store,1) = "P" then
' our process code
If columnV.ContainsKey(store) Then
end if
Next
So you can use Strings.Right(some text,1) to get the right most character. You simply then have a if/then block around that code, and thus you skip anything that does not have a store with "P" as the last letter. The above is air code, but the simple concept here is to first: Split out the line into the correct parts.
Check if store ends in "P" with the above if/then, and thus only stores ending in P will be processed.
However, your sample code and the variable names used really does not make a lot of sense.
回答2:
It appears as if a record can be represented across multiple lines, but not a defined number of multiple lines (e.g. 001P is over 4 lines but 002 is over 3 lines).
It also appears as if the line represents the data in a {property} - {value} format.
The first thing that I would do is create a class to represent your record.
The second thing would be to get every line from your text file and iterate over them.
The third thing would be take the incoming information and convert it to your custom class which would be added to a List.
The last thing would be to then filter the List where Stores do not contain the letter "P".
Here is the code, in action:
Imports System
Imports System.Collections.Generic
Imports System.Linq
Public Module Module1
Public Sub Main()
IO.File.WriteAllLines("test.txt", {
"Store - 001P",
"Owner - Greg",
"Price - 45000",
"Employees - 30",
"Store - 002",
"Owner - Jen",
"Price - 34400"
})
Dim lines() As String = IO.File.ReadAllLines("test.txt")
Dim stores As List(Of Store) = ConvertLinesToStores(lines)
Dim storesWithP() As Store = stores.Where(Function(s) s.StoreId.Contains("P")).ToArray()
Console.WriteLine("Stores with P: ")
Console.WriteLine(String.Join(Environment.NewLine, storesWithP.Select(Function(s) s.StoreId).ToArray()))
End Sub
Private Function ConvertLinesToStores(ByVal lines() As String) As List(Of Store)
Dim stores As New List(Of Store)
Dim item As Store
For Each line As String In lines
Dim parts() As String = line.Split(" - ")
If (lines.Length < 3) Then
Continue For
End If
Dim propertyName As String = parts(0)
Dim propertyValue As String = parts(2)
Dim employeeCount As Integer
If (propertyName = "Store") Then
If (item IsNot Nothing) Then
stores.Add(item)
End If
item = New Store() With {.StoreId = propertyValue}
ElseIf (propertyName = "Owner") Then
item.Owner = propertyValue
ElseIf (propertyName = "Price") Then
item.Price = propertyValue
ElseIf (propertyName = "Employees" AndAlso Integer.TryParse(propertyValue, employeeCount)) Then
item.EmployeeCount = employeeCount
End If
Next
If (item IsNot Nothing) Then
stores.Add(item)
End If
Return stores
End Function
End Module
Public Class Store
Public Property StoreId As String
Public Property Owner As String
Public Property Price As Integer
Public Property EmployeeCount As Integer
End Class
Fiddle: Live Demo
回答3:
Assuming your text file has a consistent pattern the following will give you a list of your stores with all the properties. My Stores.txt looks like this...
Store - 001P
Owner - Greg
Price - 45000
Employees - 30
Store - 002
Owner- Jen
Price - 34400
Employees - 20
Store - 03P
Owner - Mary
Price - 50000
Employees - 22
Store - 04P
Owner - Bill
Price - 42000
Employees - 90
I created a simple class to hold the store data.
Public Class Store
Public Property ID As String
Public Property Owner As String
Public Property Price As Decimal
Public Property Employees As Integer
End Class
First I read the file getting an array of lines. I loop through the lines of the file skipping ahead by 5 on each iteration (Step 5).This should hit the Store line (Store appears every 5 lines).
If it contains a P then I create a new Store and set it properties by moving down one line (the i + 1 etc.). After the properties are set, I add the Store to the list.
Now you have a List(Of Store) containing only the stores who's Id contains a P. You can access the items by index or in a For Each loop and have all the properties available.
Private StoreList As New List(Of Store)
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim lines = File.ReadAllLines("C:\Users\maryo\Desktop\Stores.txt")
For i = 0 To lines.Length - 4 Step 5
Dim ID = lines(i).Split("-"c)(1).Trim
If ID.Contains("P") Then
Dim st As New Store
st.ID = ID
st.Owner = lines(i + 1).Split("-"c)(1).Trim
st.Price = CDec(lines(i + 2).Split("-"c)(1).Trim)
st.Employees = CInt(lines(i + 3).Split("-"c)(1).Trim)
StoreList.Add(st)
End If
Next
'Just to check if my list contains what I expected.
DataGridView1.DataSource = StoreList
End Sub
来源：https://stackoverflow.com/questions/64135770/skip-block-of-text-from-adding-to-dictionary-vb-net