怎样把 001,002, 字符（两组数、两个逗号）转换为stu_id in ('001','002')

Question

001,002,003， 是字符串
要转换为 '001','002','003'
其实问题就是 
    1，删掉后面一个逗号,
    2，然后将逗号替换为 ',' （逗号+引号）
       可是我在用 replace（",","','"）时总是只能替换第一个逗号！

Answer 1

s="'adf,sdfs,asdf,sfdsdf,sdf'";
r=s.split(",")
i=0;
s=""
while(r[i]){
s+=r[i]+"','"
i++;
}

Answer 2

s="'adf,sdfs,asdf,sfdsdf,sdf'"
r=s.split(",")
i=0
s=""
while(r[i+1]){
s+=r[i]+"','"
i++
}
s+=r[i]

Answer 3

function replaceAll(s,s1,s2)
r=s.split(",")
i=0
t=""
while(r[i+1]){
t+=r[i]+"','"
i++
}
t+=r[i]
return t
}
呵呵 不好意思