>>> all_users = ["qiwsir","github"]
>>> all_users.append("io")
>>> all_users
['qiwsir', 'github', 'io']

>>> all_users
['qiwsir', 'github', 'io']
>>> all_users.insert("python")   #list.insert(i,x),要求有兩個(gè)參數(shù)，少了就報(bào)錯(cuò)
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
TypeError: insert() takes exactly 2 arguments (1 given)

>>> all_users.insert(0,"python")
>>> all_users
['python', 'qiwsir', 'github', 'io']

>>> all_users.insert(1,"http://")
>>> all_users
['python', 'http://', 'qiwsir', 'github', 'io']

>>> length = len(all_users)
>>> length
5

>>> all_users.insert(length,"algorithm")
>>> all_users
['python', 'http://', 'qiwsir', 'github', 'io', 'algorithm']

list.remove(x)
Remove the first item from the list whose value is x. It is an error if there is no such item.
list.pop([i])
Remove the item at the given position in the list, and return it. If no index is specified, a.pop() removes and returns the last item in the list. (The square brackets around the i in the method signature denote that the parameter is optional, not that you should type square brackets at that position. You will see this notation frequently in the Python Library Reference.)

>>> all_users
['python', 'http://', 'qiwsir', 'github', 'io', 'algorithm']
>>> all_users.remove("http://")
>>> all_users    #的確是把"http://"刪除了
['python', 'qiwsir', 'github', 'io', 'algorithm']

>>> all_users.remove("tianchao")    #原list中沒有“tianchao”，要?jiǎng)h除，就報(bào)錯(cuò)。
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
ValueError: list.remove(x): x not in list

>>> all_users
['python', 'qiwsir', 'github', 'io', 'algorithm']
>>> "python" in all_users    #這里用in來判斷一個(gè)元素是否在list中，在則返回True，否則返回False
True

>>> if "python" in all_users:
...   all_users.remove("python")
...   print all_users
... else:
...   print "'python' is not in all_users"
... 
['qiwsir', 'github', 'io', 'algorithm']   #刪除了"python"元素

>>> if "python" in all_users:
...   all_users.remove("python")
...   print all_users
... else:
...   print "'python' is not in all_users"
... 
'python' is not in all_users    #因?yàn)橐呀?jīng)刪除了，所以就沒有了。

>>> all_users
['qiwsir', 'github', 'io', 'algorithm']
>>> all_users.pop()   #list.pop([i]),圓括號(hào)里面是[i]，表示這個(gè)序號(hào)是可選的
'algorithm'       #如果不寫，就如同這個(gè)操作，默認(rèn)刪除最后一個(gè)，并且將該結(jié)果返回

>>> all_users
['qiwsir', 'github', 'io']

>>> all_users.pop(1)    #指定刪除編號(hào)為1的元素"github"
'github'

>>> all_users
['qiwsir', 'io']
>>> all_users.pop()
'io'

>>> all_users      #只有一個(gè)元素了，該元素編號(hào)是0
['qiwsir']
>>> all_users.pop(1)  #但是非要?jiǎng)h除編號(hào)為1的元素，結(jié)果報(bào)錯(cuò)。注意看報(bào)錯(cuò)信息
Traceback (most recent call last):
 File "<stdin>", line 1, in <module>
IndexError: pop index out of range   #刪除索引超出范圍，就是1不在list的編號(hào)范圍之內(nèi)