大佬们，我想给magicians列表中每个元素开头加个gre

你 name = changing_name这句在函数中定义了以个局部变量names，不是全局变量names

数组类型的全局变量在函数体内是可以增、删、改的，所以可以这样：
def show_magician():
for name in magicians:
print(name.title())
def make_great():
for i in range(len(magicians)):
magicians[i] = 'Great Magician: ' + magicians[i]
magicians = ['zhang san', 'li si', 'wang er', 'ma zi']
make_great()
show_magician()