关于函数形参为可变数据类型的一道题

def extendList(val, list = []):
    list.append(val)
    return list


list1 = extendList(10)  #[10,]  list
list2 = extendList(123, []) #[123,]
list3 = extendList('a') #[10, 'a']  list

print('list=%s' % list1)    #[10, 'a']  list
print('list=%s' % list2)    #[123,]
print('list=%s' % list3)    #[10, 'a']  list

 

def extendList(val, list=[]):
    list.append(val)
    return list


list1 = extendList(10)
print('list=%s' % list1)    #[10,]
list2 = extendList(123, [])
print('list=%s' % list2)    #[123,]
list3 = extendList('a')
print('list=%s' % list3)    #[10, 'a']