dim函數(shù)的第三個(gè)參數(shù)，也就是截取字符的長(zhǎng)度，我在設(shè)置這個(gè)的時(shí)候，出了些問(wèn)題:response.write mid(up_address,a(i),a(i+1)-1) “br />”像我上面這樣寫的時(shí)候，它就會(huì)報(bào)錯(cuò)，提示無(wú)效的過(guò)程調(diào)用或參數(shù),
response.write mid(up_address,a(i),a(i+1)+1) “br />”但是當(dāng)我把其中的a(i+1)-1改為a(i+1)+1時(shí)，就能執(zhí)行了,a(i+1)對(duì)應(yīng)的值是11，可為什么只能減不能加呢?全部代碼如下:
VB code:
復(fù)制代碼 代碼如下:
dim a(),up_address
up_address = "aaa djaldk adflj adafadfasdfa afd ad"
redim a(len(up_address))
a(0) = instr(up_address," ")
response.write a(0) "br />"
if a(0)>0 then
for i=0 to len(up_address)-1
a(i+1) = instr(a(i)+1,up_address," ")
response.write mid(up_address,a(i),a(i+1)-1) "br />"
if a(i+1)=0 then
exit for
end if
response.write a(i+1) "br />"
next
end if如上代碼，我是想把字符串按空格分解出來(lái)，但是mid的第三個(gè)參數(shù)那出了點(diǎn)問(wèn)題，我本來(lái)是想這樣截取的：
VB code：
復(fù)制代碼 代碼如下:
mid(up_address,a(i),a(i+1)-a(i)-1)
‘a(chǎn)(i)是空格的位置
‘a(chǎn)(i+1)是下一個(gè)空格的位置
‘a(chǎn)(i+1)-a(i)-1是兩個(gè)空格直間的字符長(zhǎng)度
現(xiàn)在的問(wèn)題是，經(jīng)測(cè)試，mid的第三個(gè)參數(shù)那，無(wú)法使用減法，也就是說(shuō)，我可以寫a(i+1)+，但不能寫a(i+1)-，想了好久，我一直不明白問(wèn)題出在哪？應(yīng)該怎么來(lái)解決呢？
出現(xiàn)這個(gè)問(wèn)題是因?yàn)樯厦娴腗ID函數(shù)的第三個(gè)參數(shù)出現(xiàn)了負(fù)數(shù),下面是在網(wǎng)上找的測(cè)試的VBS代碼，原理一樣，如下的代碼：
VBScript code:
復(fù)制代碼 代碼如下:
dim a(),up_address
up_address = "aaa djaldk adflj adafadfasdfa afd ad"
MsgBox len(up_address) '36
redim a(len(up_address)) 'a(36)
a(0) = instr(up_address," ")
MsgBox a(0) 'a(0)=4
MsgBox a(0) "br />"
if a(0)>0 then
for i=0 to len(up_address)-1
a(i+1) = instr(a(i)+1,up_address," ")
MsgBox a(i) " " (a(i+1)-1)‘這里的結(jié)果為34，-1，所以導(dǎo)致出錯(cuò)
MsgBox mid(up_address,a(i),a(i+1)-1) "br />"
if a(i+1)=0 then
exit for
end if
MsgBox a(i+1) "br />"
next
end if
