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<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>1.8. 数据结构</title><link rel="stylesheet" type="text/css" href="../docbook.css" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><meta name="keywords" content="php,pear,pecl,phar, python, , " /><link rel="home" href="../index.html" title="Netkiller Python 手札" /><link rel="up" href="index.html" title="第 1 章 Python 入门" /><link rel="prev" href="type.html" title="1.7. 数据类型" /><link rel="next" href="python.serializable.html" title="1.9. 序列化" /></head><body><a xmlns="" href="//www.netkiller.cn/">Home</a> | <a xmlns="" href="//netkiller.github.io/">简体中文</a> | <a xmlns="" href="http://netkiller.sourceforge.net/">繁体中文</a> | <a xmlns="" href="/journal/index.html">杂文</a>
| <a xmlns="" href="https://github.com/netkiller">Github</a> | <a xmlns="" href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a> | <a xmlns="" href="https://www.facebook.com/bg7nyt">Facebook</a> | <a xmlns="" href="http://cn.linkedin.com/in/netkiller/">Linkedin</a> | <a xmlns="" href="https://www.youtube.com/user/bg7nyt/videos">Youtube</a> | <a xmlns="" href="//www.netkiller.cn/home/donations.html">打赏(Donations)</a> | <a xmlns="" href="//www.netkiller.cn/home/about.html">About</a><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">1.8. 数据结构</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="type.html">上一页</a> </td><th width="60%" align="center">第 1 章 Python 入门</th><td width="20%" align="right"> <a accesskey="n" href="python.serializable.html">下一页</a></td></tr></table><hr /></div><table xmlns=""><tr><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=watch&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&repo=netkiller.github.io&type=fork&count=true&size=large" height="30" width="170" frameborder="0" scrolling="0" style="width:170px; height: 30px;" allowTransparency="true"></iframe></td><td><iframe src="//ghbtns.com/github-btn.html?user=netkiller&type=follow&count=true&size=large" height="30" width="240" frameborder="0" scrolling="0" style="width:240px; height: 30px;" allowTransparency="true"></iframe></td><td></td><td><a href="https://zhuanlan.zhihu.com/netkiller"><img src="/images/logo/zhihu-card-default.svg" height="25" /></a></td><td valign="middle"><a href="https://zhuanlan.zhihu.com/netkiller">知乎专栏</a></td><td></td><td></td><td></td><td></td></tr></table><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="python.datastruct"></a>1.8. 数据结构</h2></div></div></div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="data.list"></a>1.8.1. List</h3></div></div></div>
<p>随机抽取list成员</p>
<pre class="screen">
import random
# random choice from a list
for i in range(5):
print random.choice([1, 2, 3, 5, 9])
</pre>
<pre class="programlisting">
test = []
test.append('1')
test.append('b')
test.append('c')
print(test)
</pre>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id872"></a>1.8.1.1. 返回索引序号</h4></div></div></div>
<p>index()方法语法：</p>
<pre class="screen">
list.index(x[, start[, end]])
参数
x-- 查找的对象。
start-- 可选，查找的起始位置。
end-- 可选，查找的结束位置。
</pre>
<pre class="programlisting">
fruits = ["apple", "banana", "cherry", "apple"]
print(fruits.index("apple")) # 输出: 0
animals = ["cat", "dog", "tiger"]
print(animals.index("dog")) # 输出: 1
numbers = [1, 2, 3, 4, 1, 1, 1, 4, 5]
print(numbers.index(4, 4, 8)) # 输出: 7
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id873"></a>1.8.1.2. 二维列表，指定列，查找最大值</h4></div></div></div>
<pre class="programlisting">
matrix = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
column = [row[1] for row in matrix]
max_value = max(column)
print("第二列最大值：", max_value)
</pre>
<p>返回最大值</p>
<pre class="programlisting">
matrix = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
column = [row[1] for row in matrix]
max_value = max(column)
index = column.index(max_value)
print(index, matrix[index])
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="list.index"></a>1.8.1.3. 获得list中最大/最小值元素的索引</h4></div></div></div>
<pre class="programlisting">
获得list中最大元素的索引
nums = [1,2,3,4,5]
nums.index(max(nums))
相应的最小值索引
nums = [1,2,3,4,5]
nums.index(min(nums))
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="list.enumerate"></a>1.8.1.4. 用 enumerate 返回 list 索引</h4></div></div></div>
<pre class="programlisting">
>>> seq = ['one', 'two', 'three']
>>> for i, element in enumerate(seq):
... print i, element
...
0 one
1 two
2 three
</pre>
<p>指定开始索引下标</p>
<pre class="programlisting">
>>> seasons = ['Spring', 'Summer', 'Fall', 'Winter']
>>> list(enumerate(seasons))
[(0, 'Spring'), (1, 'Summer'), (2, 'Fall'), (3, 'Winter')]
>>> list(enumerate(seasons, start=1)) # 下标从 1 开始
[(1, 'Spring'), (2, 'Summer'), (3, 'Fall'), (4, 'Winter')]
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id874"></a>1.8.1.5. 二维列表 LIST 排序</h4></div></div></div>
<pre class="screen">
# 定义一个二维列表
lst = [[4, 2], [1, 5], [3, 3], [2, 1]]
# 使用sorted()函数和lambda表达式按照二维列表的第一列进行排序
sorted_lst = sorted(lst, key=lambda x: x[0])
print(sorted_lst)
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id875"></a>1.8.1.6. 列表相减运算</h4></div></div></div>
<pre class="screen">
a = ['a', 'b', 'c', 'd']
b = ['b', 'c']
# 方法1：使用列表推导式（简洁高效）
result = [x for x in a if x not in b]
print("方法1结果:", result) # 输出: ['a', 'd']
# 方法2：使用filter函数（函数式编程风格）
result = list(filter(lambda x: x not in b, a))
print("方法2结果:", result) # 输出: ['a', 'd']
# 方法3：循环遍历（原地修改原列表，不推荐但适合理解过程）
a_copy = a.copy() # 复制原列表避免遍历中修改导致的问题
for item in a_copy:
if item in b:
a.remove(item)
print("方法3结果:", a) # 输出: ['a', 'd']
</pre>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="data.set"></a>1.8.2. Set 集合</h3></div></div></div>
<pre class="programlisting">
>>> ','.join(set);
'four,three,two,one'
>>> set('four,three,two,one'.split(','));
{'one', 'four', 'three', 'two'}
>>> fruit = [ 'banana', 'orange', 'pineapple' ]
>>> set(fruit)
{'banana', 'pineapple', 'orange'}
</pre>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id876"></a>1.8.2.1. 创建集合</h4></div></div></div>
<pre class="programlisting">
>>> set = {'a','b','c'}
>>> set
set(['a', 'c', 'b'])
>>> set = {"one", "two", "three","one"}
>>> set
set(['three', 'two', 'one'])
</pre>
<pre class="programlisting">
set1 = {1, 2, 3, 4}
print(set1)
set2 = set([4, 5, 6, 7])
print(set2)
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id877"></a>1.8.2.2. 添加元素</h4></div></div></div>
<p>添加元素到集合有两个方法，分别是 add() 和 update()</p>
<pre class="programlisting">
>>> set.add('four')
>>> set
set(['four', 'three', 'two', 'one'])
</pre>
<pre class="programlisting">
company = set(("Google", "OpenAI", "Facebook"))
company.update({"Microsoft"})
company.update({"Aliyun","Taobao"})
print(company)
company.update([1,2],[5,6])
print(company)
</pre>
<pre class="screen">
{'Facebook', 'Google', 'Microsoft', 'Taobao', 'Aliyun', 'OpenAI'}
{'Facebook', 1, 2, 5, 6, 'Aliyun', 'Google', 'OpenAI', 'Microsoft', 'Taobao'}
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id878"></a>1.8.2.3. 删除元素</h4></div></div></div>
<pre class="programlisting">
company = set({'Facebook', 'Google', 'Microsoft', 'Taobao', 'Aliyun', 'OpenAI'})
print(company)
company.remove("OpenAI")
print(company)
company.discard("Aliyun")
print(company)
</pre>
<p>随机移除一个元素</p>
<pre class="programlisting">
company.pop()
print(company)
</pre>
<p></p>
<pre class="screen">
{'Taobao', 'Facebook', 'Aliyun', 'Microsoft', 'OpenAI', 'Google'}
{'Taobao', 'Facebook', 'Aliyun', 'Microsoft', 'Google'}
{'Taobao', 'Facebook', 'Microsoft', 'Google'}
{'Facebook', 'Microsoft', 'Google'}
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id879"></a>1.8.2.4. 清空集合</h4></div></div></div>
<pre class="programlisting">
>>> company = set(("Google", "Microsoft", "OpenAI"))
>>> company.clear()
>>> print(company)
set()
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id880"></a>1.8.2.5. 合并集合</h4></div></div></div>
<pre class="programlisting">
x = {"apple", "banana", "cherry"}
y = {"google", "microsoft", "apple"}
z = x.union(y)
print(z)
</pre>
<p></p>
<pre class="programlisting">
x = {"a", "b", "c"}
y = {"d", "e", "f"}
z = {"g", "i", "j"}
result = x.union(y, z)
print(result)
</pre>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="data.dict"></a>1.8.3. Dict 字典</h3></div></div></div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id881"></a>1.8.3.1. 随机选择字典的 key 和 value</h4></div></div></div>
<p>随机字典的 key 和 value</p>
<pre class="screen">
<![CDATA[
names = {1: '张三', 2: '李四', 3: '王五', 4: '赵六', 5: '牛七', 6: '马八'}
print(random.choice(list(names.keys())))
print(random.choice(list(names.values())))
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id882"></a>1.8.3.2. 字典合并</h4></div></div></div>
<pre class="screen">
dict1 = {'name','neo'}
dict2 = {'nickname','netkiller'}
dict1.update(dict2)
print(dict1)
</pre>
<p></p>
<pre class="screen">
{'name', 'neo', 'nickname', 'netkiller'}
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id883"></a>1.8.3.3. 取 Value 最大值</h4></div></div></div>
<pre class="programlisting">
data = {
"Neo": 5,
"Netkiller": 10,
"BG7NYT": 8,
}
ret = max(data, key=lambda x: data[x])
print(ret)
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id884"></a>1.8.3.4. 指定 key 取 value 最大值</h4></div></div></div>
<pre class="programlisting">
data = [
{
"question": "为什么过只加汇摇晃",
"answer": "因为支架是由很多支索小圆轮组成的，所以吊厢过索轮时会有轻微的震动和摇晃，这些都是正常的",
"ratio": 0,
"distance": 41.112388610839844
},
{
"question": "吊厢过之家为什么会摇晃",
"answer": "因为支架是由很多支索小圆轮组成的，所以吊厢过索轮时会有轻微的震动和摇晃，这些都是正常的",
"ratio": 0,
"distance": 42.78510284423828
},
{
"question": "嗦道为啥会摇晃",
"answer": "因为支架是由很多支索小圆轮组成的，所以吊厢过索轮时会有轻微的震动和摇晃，这些都是正常的",
"ratio": 1,
"distance": 44.00849914550781
}
]
ret = max(data, key=lambda dic: dic['ratio'])
print(ret)
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id885"></a>1.8.3.5. 字典求和</h4></div></div></div>
<pre class="programlisting">
count = sum(dict.values())
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id886"></a>1.8.3.6. 对 value 排序后返回 key</h4></div></div></div>
<pre class="programlisting">
data = {
"Neo": 5,
"Netkiller": 10,
"BG7NYT": 8,
}
ret = sorted(data, key=lambda x: data[x])
print(ret)
ret = sorted(data, key=lambda x: data[x],reverse=True)
print(ret)
ret = sorted(data, key=lambda x: data[x],reverse=False)
print(ret)
</pre>
<p>返回结果</p>
<pre class="screen">
['Neo', 'BG7NYT', 'Netkiller']
['Netkiller', 'BG7NYT', 'Neo']
['Neo', 'BG7NYT', 'Netkiller']
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id887"></a>1.8.3.7. 两个 list 合并为 dict</h4></div></div></div>
<p>python header = ['a','b','c'] body=[1,2,3] 转成 dict. {'a':1,
'b': 2, 'c':3}
</p>
<pre class="programlisting">
可以使用 Python 的 zip() 函数将两个列表合并为字典，zip() 会将对应索引的元素配对，然后通过 dict() 转换为字典：
将两个列表转换为字典
原理说明：
zip(header, body) 会将两个列表中对应位置的元素组合成元组，形成类似 [('a', 1), ('b', 2), ('c', 3)] 的可迭代对象。
dict() 函数会将这些元组转换为字典，元组的第一个元素作为键，第二个元素作为值。
注意事项：
如果两个列表长度不一致，zip() 会以较短的列表为准，忽略超出部分的元素。
例如：header = ['a', 'b']，body = [1, 2, 3]，结果会是 {'a': 1, 'b': 2}。
header = ['a', 'b', 'c']
body = [1, 2, 3]
# 使用zip()配对后转换为字典
result_dict = dict(zip(header, body))
print(result_dict) # 输出: {'a': 1, 'b': 2, 'c': 3}
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h4 class="title"><a id="id888"></a>1.8.3.8. 计算 value 的数量</h4></div></div></div>
<pre class="programlisting">
data = {
'产品目标': ['竞品分析'],
'开发目标': ['编码开发', '代码测试'],
'运营目标': ['区域投放']
}
# 计算每个value的数量
count_result = {key: len(value) for key, value in data.items()}
print("每个目标包含的子项数量：")
for key, count in count_result.items():
print(f"{key}：{count}个")
</pre>
</div>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="Iterator"></a>1.8.4. Iterator</h3></div></div></div>
<pre class="programlisting">
#!/usr/bin/python
# -*- coding: UTF-8 -*-
# 创建 Iterator 对象
it = iter([1, 2, 3, 4, 5])
# 开始循环
while True:
try:
# 获得下一个值
x = next(it)
print(x)
except StopIteration:
# 遇到StopIteration终止循环
break
</pre>
<p>设置结束标志符</p>
<pre class="programlisting">
#!/usr/bin/python
# -*- coding: UTF-8 -*-
it = iter([1, 2, 5, 4, 3])
while True:
x = next(it, 'a')
print(x)
if x == 'a':
break
</pre>
</div>
<div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="python.queue"></a>1.8.5. 队列</h3></div></div></div>
<pre class="programlisting">
import queue
q = queue.SimpleQueue()
for n in range(10):
q.put(n)
print("队列数量:", q.qsize())
while not q.empty():
print(q.get())
print("队列状态：", q.empty())
</pre>
<p>先进先出队列，保持队列最大尺寸，超过尺寸自动出队</p>
<pre class="programlisting">
from queue import Queue
q = Queue(maxsize=3)
for i in range(10):
if q.full():
q.get()
q.put(i, block=False)
print(type(q.queue), q.queue)
while not q.empty():
i = q.get(block=False)
print(i)
</pre>
<pre class="programlisting">
from queue import Queue
q = Queue(maxsize=10)
for i in range(20):
if q.full():
q.get()
q.put(i, block=False)
print(type(q.queue), q.queue)
for n in range(5):
if not q.empty():
i = q.get(block=False)
print(i)
</pre>
</div>
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