字符串函数举例 d=mid (a, 2, 3) print d wer print len(a) 7 print instr(l, a "r'n print instr(a, t) 5 <<> 2021/222 82021/2/22 8 字符串函数举例 d=mid(a,2,3) print d wer print len(a) 7 print instr(1,a,"r") 4 print instr(a,"t") 5