修剪字符串末尾的最后一个字符

Question

I have a loop that is creating a string until the end of the file. Depending on how many products I have at the time. I need to trim the last comma at the end.

I get:

{ sku: '6200', display_name:'Product 1', unit_price: 497.37, qty: 1 },  
{ sku: '2344', display_name:'Product 2', unit_price: 824.21, qty: 1 },

I need:

{ sku: '6200', display_name:'Product 1', unit_price: 497.37, qty: 1 },  
{ sku: '2344', display_name:'Product 2', unit_price: 824.21, qty: 1 }

Loop:

<%
set rsheadercart = db.execute(sqlheadercart)
    if not rsheadercart.eof then 
        do until rsheadercart.eof 




            items = items & " { sku: '" & rsheadercart("ten_digit_part_number") & "',"
            items = items & " display_name:'" & rsheadercart("part_name") & "',"
            items = items & " unit_price: " & rsheadercart("price") & ","
            items = items & " qty: " & rsheadercart("quantity") & " }, "


        rsheadercart.movenext
        loop 
        %>
<%
end if 
%>

Answer 1

Have found the simplest way over the years is to let the loop generate the extra character than just trim it after the execution of the loop using Left() .

After your loop add;

items = Left(items, Len(items) - 1)

This way avoids having to add a load of logic into the loop to handle the edge cases unnecessarily.

Answer 2

Move your comma to the beginning of the loop and put it in a conditional statement so that it isn't executed at the first iteration

do until rsheadercart.eof 

    If items <> "" then 
       items = items & ","
    End If     

    items = items & " { sku: '" & rsheadercart("ten_digit_part_number") & "',"
    items = items & " display_name:'" & rsheadercart("part_name") & "',"
    items = items & " unit_price: " & rsheadercart("price") & ","
    items = items & " qty: " & rsheadercart("quantity") & " } "

rsheadercart.movenext
loop 

Answer 3

In cases like that I often use the Join method

dim itemList 
set itemList = CreateObject("System.Collections.ArrayList")
do until rsheadercart.eof 
    dim item       
    item = " { sku: '" & rsheadercart("ten_digit_part_number") & "',"
    item = item & " display_name:'" & rsheadercart("part_name") & "',"
    item = item & " unit_price: " & rsheadercart("price") & ","
    item = item & " qty: " & rsheadercart("quantity") & " } "
    itemList.Add item
    rsheadercart.movenext
loop 
items = Join(itemList.ToArray,",")

If you don't want to use an Arraylist, you can do the same with an plain array, but you would have to redim it each iteration.