将字符串拆分为2中的第n个分隔符

def find_nth_occurrence(string, delimiter, n):
    start = -1
    for i in range(n):
        start = string.find(delimiter, start + 1)
        if start == -1:
            break
    return start

string = "abc,def,ghi,jkl,mno,pqr"
delimiter = ","
n = 2
index = find_nth_occurrence(string, delimiter, n)

if index != -1:
    first_part = string[:index]
    second_part = string[index + 1:]
    print("第{}个分隔符的前半部分：{}".format(n, first_part))
    print("第{}个分隔符的后半部分：{}".format(n, second_part))
else:
    print("找不到第{}个分隔符".format(n))