#pythonslicing和函数range差不多，起始值，最后值，步长值a='abcdefghijklmnopqrstuvwxyz'print(a[:],end='\n')#abcdefghijklmnopqrstuvwxyzprint(a[:5],end='\n')#abcdeprint(a[:-1],end='\n')#abcdefghijklmnopqrstuvwxy