标签:删除 列表项 pytho 更新 不同 not bsp ble 重复
列表创建
创建一个列表,只要用逗号分隔不同的数据项使用方括号括起来即可,例如:
first_list = ["hello","python",1900,1970]
列表访问
使用下标索引访问列表中的值,也可通过方括号进行截取。例如:
>>> first_list = ["hello","python",1900,1970]
>>> first_list[0]
‘hello‘
>>> first_list[1:3]
[‘python‘, 1900]
列表更新
可以索引对列表的数据项进行修改或更新,也可用append方法来增加列表项,例如:
>>> first_list = ["hello","python",1900,1970]
>>> first_list[1] = "yangyang"
>>> first_list
[‘hello‘, ‘yangyang‘, 1900, 1970]
append例子,例如:
>>> first_list = ["hello","python",1900,1970]
>>> first_list.append(2017)
>>> first_list
[‘hello‘, ‘yangyang‘, 1900, 1970, 2017]
列表元素删除
使用del删除列表中的元素,例如:
>>> first_list = ["hello","python",1900,1970]
>>> del first_list[3]
>>> first_list
[‘hello‘, ‘python‘, 1900]
列表截取
>>> first_list = ["hello","python",1900,1970]
>>> first_list[1]
‘python‘
>>> first_list[-2]
1900
>>> first_list[1:3]
[‘python‘, 1900]
>>> first_list[1:]
[‘python‘, 1900, 1970]
>>> first_list[-1:-3:-1]
[1970, 1900]
列表操作符:+、*、[]、[:]、in、not in、for i in list
a = ["hello","python"],b = ["hello","yangyang"]
操作符 | 描述 | 实例 |
+ | 组合 |
>>> a = ["hello","python"] |
* | 重复 |
>>> a * 4 |
[] | 索引 |
>>> a[0] |
[:] | 截取 |
>>> a[0:2] |
in | 成员运算符,元素在列表中返回True |
>>> "hello" in a |
not in | 成员运算符,元素不在列表中返回True |
>>> "world" not in a |
for i in list | 迭代 |
>>> for i in a: hello |
标签:删除 列表项 pytho 更新 不同 not bsp ble 重复
原文地址:http://www.cnblogs.com/yangyangchunchun/p/7269502.html