list append()和extend()区别

append()

• 添加单一元素在末尾

my_list = ['geeks', 'for'] 
my_list.append('geeks') 
print(my_list) 

output:

['geeks', 'for', 'geeks']

• 添加一个list后，也是只添加一个list对象

my_list = ['geeks', 'for', 'geeks'] 
another_list = [6, 0, 4, 1] 
my_list.append(another_list) 
print(my_list) 

output:

['geeks', 'for', 'geeks', [6, 0, 4, 1]]

extend()

• 迭代的添加每一个元素到list中，如果添加一个list则会添加list中元素个数的数量元素

my_list = ['geeks', 'for'] 
another_list = [6, 0, 4, 1] 
my_list.extend(another_list) 
print(my_list)

outputs:

['geeks', 'for', 6, 0, 4, 1]

my_list = ['geeks', 'for'] 
another_list = [6, 0, 4, [1, 2]] 
my_list.extend(another_list) 
print(my_list)

output:

['geeks', 'for', 6, 0, 4, [1, 2]]

• 字符串是iterable，所以会添加每一个字符到list中

my_list = ['geeks', 'for', 6, 0, 4, 1] 
my_list.extend('geeks') 
print(my_list)

outputs:

['geeks', 'for', 6, 0, 4, 1, 'g', 'e', 'e', 'k', 's']