内置函数就是Python给你提供的, 拿来直接用的函数，比如print，input等。
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截止到python版本3.6.2 ，一共提供了68个内置函数，具体如下
<span class="hljs-selector-tag">abs() <span class="hljs-selector-tag">dict() <span class="hljs-selector-tag">help() <span class="hljs-selector-tag">min() <span class="hljs-selector-tag">setattr() <span class="hljs-keyword">all() <span class="hljs-selector-tag">dir() <span class="hljs-selector-tag">hex() <span class="hljs-selector-tag">next() <span class="hljs-selector-tag">slice() <span class="hljs-selector-tag">any() <span class="hljs-selector-tag">divmod() <span class="hljs-selector-tag">id() <span class="hljs-selector-tag">object() <span class="hljs-selector-tag">sorted() <span class="hljs-selector-tag">ascii() <span class="hljs-selector-tag">enumerate() <span class="hljs-selector-tag">input() <span class="hljs-selector-tag">oct() <span class="hljs-selector-tag">staticmethod() <span class="hljs-selector-tag">bin() <span class="hljs-selector-tag">eval() <span class="hljs-selector-tag">int() <span class="hljs-selector-tag">open() <span class="hljs-selector-tag">str() <span class="hljs-selector-tag">bool() <span class="hljs-selector-tag">exec() <span class="hljs-selector-tag">isinstance() <span class="hljs-selector-tag">ord() <span class="hljs-selector-tag">sum() <span class="hljs-selector-tag">bytearray() fi<span class="hljs-selector-tag">lter() <span class="hljs-selector-tag">issubclass() <span class="hljs-selector-tag">pow() <span class="hljs-selector-tag">super() <span class="hljs-selector-tag">bytes() fl<span class="hljs-selector-tag">oat() <span class="hljs-selector-tag">iter() <span class="hljs-selector-tag">print() <span class="hljs-selector-tag">tuple() <span class="hljs-selector-tag">callable() <span class="hljs-selector-tag">format() <span class="hljs-selector-tag">len() <span class="hljs-selector-tag">property() <span class="hljs-selector-tag">type() <span class="hljs-selector-tag">chr() <span class="hljs-selector-tag">frozenset() <span class="hljs-selector-tag">list() <span class="hljs-selector-tag">range() <span class="hljs-selector-tag">vars() <span class="hljs-selector-tag">classmethod() <span class="hljs-selector-tag">getattr() <span class="hljs-selector-tag">locals() <span class="hljs-selector-tag">repr() <span class="hljs-selector-tag">zip() <span class="hljs-selector-tag">compile() <span class="hljs-selector-tag">globals() <span class="hljs-selector-tag">map() <span class="hljs-selector-tag">reversed() <span class="hljs-selector-tag">__import__() <span class="hljs-selector-tag">complex() <span class="hljs-selector-tag">hasattr() <span class="hljs-selector-tag">max() <span class="hljs-selector-tag">round() <span class="hljs-selector-tag">delattr() <span class="hljs-selector-tag">hash() <span class="hljs-selector-tag">memoryview() <span class="hljs-selector-tag">set() </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
www#gaodaima.com来源[email protected]搞@^&代*@码)网搞代码
本文将这68个内置函数综合整理为12大类，正在学习Python基础的读者一定不要错过，建议收藏学习！
- 和数字相关
- 1. 数据类型
- 2. 进制转换
- 3. 数学运算
- 和数据结构相关
- 1. 序列
- 2. 数据集合
- 3. 相关内置函数
- 和作用域相关
- 和迭代器生成器相关
- 字符串类型代码的执行
- 输入输出
- 内存相关
- 文件操作相关
- 模块相关
- 帮 助
- 调用相关
- 查看内置属性
和数字相关
1. 数据类型
- bool : 布尔型(True,False)
- int : 整型(整数)
- float : 浮点型(小数)
- complex : 复数
2. 进制转换
- bin() 将给的参数转换成二进制
- otc() 将给的参数转换成八进制
- hex() 将给的参数转换成十六进制
<span class="hljs-keyword">print(bin(<span class="hljs-number">10)) <span class="hljs-comment"># 二进制:0b1010 <span class="hljs-keyword">print(<span class="hljs-keyword">hex(<span class="hljs-number">10)) <span class="hljs-comment"># 十六进制:0xa <span class="hljs-keyword">print(<span class="hljs-keyword">oct(<span class="hljs-number">10)) <span class="hljs-comment"># 八进制:0o12 </span></span></span></span></span></span></span></span></span></span></span>
3. 数学运算
- abs() 返回绝对值
- divmode() 返回商和余数
- round() 四舍五入
- pow(a, b) 求a的b次幂, 如果有三个参数. 则求完次幂后对第三个数取余
- sum() 求和
- min() 求最小值
- max() 求最大值
<span class="hljs-keyword">print(<span class="hljs-keyword">abs(-<span class="hljs-number">2)) <span class="hljs-comment"># 绝对值:2 <span class="hljs-keyword">print(divmod(<span class="hljs-number">20,<span class="hljs-number">3)) <span class="hljs-comment"># 求商和余数:(6,2) <span class="hljs-keyword">print(round(<span class="hljs-number">4.50)) <span class="hljs-comment"># 五舍六入:4 <span class="hljs-keyword">print(round(<span class="hljs-number">4.51)) <span class="hljs-comment">#5 <span class="hljs-keyword">print(pow(<span class="hljs-number">10,<span class="hljs-number">2,<span class="hljs-number">3)) <span class="hljs-comment"># 如果给了第三个参数. 表示最后取余:1 <span class="hljs-keyword">print(sum([<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5,<span class="hljs-number">6,<span class="hljs-number">7,<span class="hljs-number">8,<span class="hljs-number">9,<span class="hljs-number">10])) <span class="hljs-comment"># 求和:55 <span class="hljs-keyword">print(min(<span class="hljs-number">5,<span class="hljs-number">3,<span class="hljs-number">9,<span class="hljs-number">12,<span class="hljs-number">7,<span class="hljs-number">2)) <span class="hljs-comment">#求最小值:2 <span class="hljs-keyword">print(max(<span class="hljs-number">7,<span class="hljs-number">3,<span class="hljs-number">15,<span class="hljs-number">9,<span class="hljs-number">4,<span class="hljs-number">13)) <span class="hljs-comment">#求最大值:15 </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
和数据结构相关
1. 序列
（1）列表和元组
- list() 将一个可迭代对象转换成列表
- tuple() 将一个可迭代对象转换成元组
<span class="hljs-keyword">print(<span class="hljs-keyword">list((<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5,<span class="hljs-number">6))) <span class="hljs-comment">#[1, 2, 3, 4, 5, 6] <span class="hljs-keyword">print(tuple([<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5,<span class="hljs-number">6])) <span class="hljs-comment">#(1, 2, 3, 4, 5, 6) </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
（2）相关内置函数
- reversed() 将一个序列翻转, 返回翻转序列的迭代器
- slice() 列表的切片
lst = <span class="hljs-string">"你好啊" <span class="hljs-literal">it = reversed(lst) <span class="hljs-comment"># 不会改变原列表. 返回一个迭代器, 设计上的一个规则 <span class="hljs-built_in">print(list(<span class="hljs-literal">it)) <span class="hljs-comment">#["啊", "好", "你"] lst = [<span class="hljs-number">1, <span class="hljs-number">2, <span class="hljs-number">3, <span class="hljs-number">4, <span class="hljs-number">5, <span class="hljs-number">6, <span class="hljs-number">7] <span class="hljs-built_in">print(lst[<span class="hljs-number">1:<span class="hljs-number">3:<span class="hljs-number">1]) <span class="hljs-comment">#[2,3] s = slice(<span class="hljs-number">1, <span class="hljs-number">3, <span class="hljs-number">1) <span class="hljs-comment"># 切片用的 <span class="hljs-built_in">print(lst[s]) <span class="hljs-comment">#[2,3] </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
（3）字符串
- str() 将数据转化成字符串
<span class="hljs-selector-tag">print(str(<span class="hljs-number">123)+<span class="hljs-string">"456") <span class="hljs-selector-id">#123456 </span></span></span></span>
- format() 与具体数据相关, 用于计算各种小数, 精算等.
<span class="hljs-keyword">s = <span class="hljs-string">"hello world!" <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-keyword">s, <span class="hljs-string">"^20")) <span class="hljs-comment">#剧中 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-keyword">s, <span class="hljs-string">"<20")) <span class="hljs-comment">#左对齐 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-keyword">s, <span class="hljs-string">">20")) <span class="hljs-comment">#右对齐 <span class="hljs-comment"># hello world! <span class="hljs-comment"># hello world! <span class="hljs-comment"># hello world! <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">3, <span class="hljs-string">"b" )) <span class="hljs-comment"># 二进制:11 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">97, <span class="hljs-string">"c" )) <span class="hljs-comment"># 转换成unicode字符:a <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11, <span class="hljs-string">"d" )) <span class="hljs-comment"># ⼗进制:11 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11, <span class="hljs-string">"o" )) <span class="hljs-comment"># 八进制:13 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11, <span class="hljs-string">"x" )) <span class="hljs-comment"># 十六进制(⼩写字母):b <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11, <span class="hljs-string">"X" )) <span class="hljs-comment"># 十六进制(大写字母):B <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11, <span class="hljs-string">"n" )) <span class="hljs-comment"># 和d⼀样:11 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">11)) <span class="hljs-comment"># 和d⼀样:11 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">123456789, <span class="hljs-string">"e" )) <span class="hljs-comment"># 科学计数法. 默认保留6位小数:1.234568e+08 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">123456789, <span class="hljs-string">"0.2e" )) <span class="hljs-comment"># 科学计数法. 保留2位小数(小写):1.23e+08 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">123456789, <span class="hljs-string">"0.2E" )) <span class="hljs-comment"># 科学计数法. 保留2位小数(大写):1.23E+08 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">1.23456789, <span class="hljs-string">"f" )) <span class="hljs-comment"># 小数点计数法. 保留6位小数:1.234568 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">1.23456789, <span class="hljs-string">"0.2f" )) <span class="hljs-comment"># 小数点计数法. 保留2位小数:1.23 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">1.23456789, <span class="hljs-string">"0.10f")) <span class="hljs-comment"># 小数点计数法. 保留10位小数:1.2345678900 <span class="hljs-keyword">print(<span class="hljs-keyword">format(<span class="hljs-number">1.23456789e+<span class="hljs-number">3, <span class="hljs-string">"F")) <span class="hljs-comment"># 小数点计数法. 很大的时候输出INF:1234.567890 </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- bytes() 把字符串转化成bytes类型
bs = bytes(<span class="hljs-string">"今天吃饭了吗", encoding=<span class="hljs-string">"utf-8") <span class="hljs-built_in">print(bs) #b<span class="hljs-string">"xe4xbbx8axe5xa4xa9xe5x90x83xe9xa5xadxe4xbax86xe5x90x97" </span></span></span></span>
- bytearray() 返回一个新字节数组. 这个数字的元素是可变的, 并且每个元素的值得范围是[0,256)
<span class="hljs-keyword">ret = bytearray(<span class="hljs-string">"alex" ,encoding =<span class="hljs-string">"utf-8") <span class="hljs-keyword">print(<span class="hljs-keyword">ret[<span class="hljs-number">0]) #<span class="hljs-number">97 <span class="hljs-keyword">print(<span class="hljs-keyword">ret) #bytearray(<span class="hljs-keyword">b<span class="hljs-string">"alex") <span class="hljs-keyword">ret[<span class="hljs-number">0] = <span class="hljs-number">65 #把<span class="hljs-number">65的位置A赋值给<span class="hljs-keyword">ret[<span class="hljs-number">0] <span class="hljs-keyword">print(str(<span class="hljs-keyword">ret)) #bytearray(<span class="hljs-keyword">b<span class="hljs-string">"Alex") </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- ord() 输入字符找带字符编码的位置
- chr() 输入位置数字找出对应的字符
- ascii() 是ascii码中的返回该值 不是就返回u
<span class="hljs-keyword">print(<span class="hljs-keyword">ord(<span class="hljs-string">"a")) <span class="hljs-comment"># 字母a在编码表中的码位:97 <span class="hljs-keyword">print(<span class="hljs-keyword">ord(<span class="hljs-string">"中")) <span class="hljs-comment"># "中"字在编码表中的位置:20013 <span class="hljs-keyword">print(<span class="hljs-keyword">chr(<span class="hljs-number">65)) <span class="hljs-comment"># 已知码位,求字符是什么:A <span class="hljs-keyword">print(<span class="hljs-keyword">chr(<span class="hljs-number">19999)) <span class="hljs-comment">#丟 <span class="hljs-keyword">for i in range(<span class="hljs-number">65536): <span class="hljs-comment">#打印出0到65535的字符 <span class="hljs-keyword">print(<span class="hljs-keyword">chr(i), end=<span class="hljs-string">" ") <span class="hljs-keyword">print(ascii(<span class="hljs-string">"@")) #"@" </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- repr() 返回一个对象的string形式
<span class="hljs-keyword">s = <span class="hljs-string">"今天 吃了%s顿 饭" % <span class="hljs-number">3 <span class="hljs-keyword">print(<span class="hljs-keyword">s)<span class="hljs-comment">#今天# 吃了3顿 饭 <span class="hljs-keyword">print(repr(<span class="hljs-keyword">s)) <span class="hljs-comment"># 原样输出,过滤掉转义字符 不管百分号% <span class="hljs-comment">#"今天 吃了3顿 饭" </span></span></span></span></span></span></span></span></span></span>
2. 数据集合
- 字典：dict 创建一个字典
- 集合：set 创建一个集合
frozenset() 创建一个冻结的集合，冻结的集合不能进行添加和删除操作。
3. 相关内置函数
- len() 返回一个对象中的元素的个数
- sorted() 对可迭代对象进行排序操作 (lamda)
语法：sorted(Iterable, key=函数(排序规则), reverse=False)
- Iterable: 可迭代对象
- key: 排序规则(排序函数), 在sorted内部会将可迭代对象中的每一个元素传递给这个函数的参数. 根据函数运算的结果进行排序
- reverse: 是否是倒叙. True: 倒叙, False: 正序
lst = [<span class="hljs-number">5,<span class="hljs-number">7,<span class="hljs-number">6,<span class="hljs-number">12,<span class="hljs-number">1,<span class="hljs-number">13,<span class="hljs-number">9,<span class="hljs-number">18,<span class="hljs-number">5] lst.sort() <span class="hljs-comment"># sort是list里面的一个方法 print(lst) <span class="hljs-comment">#[1, 5, 5, 6, 7, 9, 12, 13, 18] ll = sorted(lst) <span class="hljs-comment"># 内置函数. 返回给你一个新列表 新列表是被排序的 print(ll) <span class="hljs-comment">#[1, 5, 5, 6, 7, 9, 12, 13, 18] l2 = sorted(lst,reverse=<span class="hljs-keyword">True) <span class="hljs-comment">#倒序 print(l2) <span class="hljs-comment">#[18, 13, 12, 9, 7, 6, 5, 5, 1] </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
<span class="hljs-comment">#根据字符串长度给列表排序 lst = [<span class="hljs-string">"one", <span class="hljs-string">"two", <span class="hljs-string">"three", <span class="hljs-string">"four", <span class="hljs-string">"five", <span class="hljs-string">"six"] <span class="hljs-function"><span class="hljs-keyword">def <span class="hljs-title">f<span class="hljs-params">(s): <span class="hljs-keyword">return len(s) l1 = sorted(lst, key=f, ) print(l1) <span class="hljs-comment">#["one", "two", "six", "four", "five", "three"] </span></span></span></span></span></span></span></span></span></span></span></span></span>
- enumerate() 获取集合的枚举对象
lst = [<span class="hljs-string">"one",<span class="hljs-string">"two",<span class="hljs-string">"three",<span class="hljs-string">"four",<span class="hljs-string">"five"] <span class="hljs-keyword">for <span class="hljs-keyword">index, el in enumerate(lst,<span class="hljs-number">1): <span class="hljs-comment"># 把索引和元素一起获取,索引默认从0开始. 可以更改 <span class="hljs-keyword">print(<span class="hljs-keyword">index) <span class="hljs-keyword">print(el) <span class="hljs-comment"># 1 <span class="hljs-comment"># one <span class="hljs-comment"># 2 <span class="hljs-comment"># two <span class="hljs-comment"># 3 <span class="hljs-comment"># three <span class="hljs-comment"># 4 <span class="hljs-comment"># four <span class="hljs-comment"># 5 <span class="hljs-comment"># five </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- all() 可迭代对象中全部是True, 结果才是True
- any() 可迭代对象中有一个是True, 结果就是True
<span class="hljs-keyword">print(all([<span class="hljs-number">1,<span class="hljs-string">"hello",<span class="hljs-keyword">True,<span class="hljs-number">9])) #<span class="hljs-keyword">True <span class="hljs-keyword">print(<span class="hljs-keyword">any([<span class="hljs-number">0,<span class="hljs-number">0,<span class="hljs-number">0,<span class="hljs-keyword">False,<span class="hljs-number">1,<span class="hljs-string">"good"])) #<span class="hljs-keyword">True </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- zip() 函数用于将可迭代的对象作为参数, 将对象中对应的元素打包成一个元组, 然后返回由这些元组组成的列表. 如果各个迭代器的元素个数不一致, 则返回列表长度与最短的对象相同
lst1 = [<span class="hljs-number">1, <span class="hljs-number">2, <span class="hljs-number">3, <span class="hljs-number">4, <span class="hljs-number">5, <span class="hljs-number">6] lst2 = [<span class="hljs-string">"醉乡民谣", <span class="hljs-string">"驴得水", <span class="hljs-string">"放牛班的春天", <span class="hljs-string">"美丽人生", <span class="hljs-string">"辩护人", <span class="hljs-string">"被嫌弃的松子的一生"] lst3 = [<span class="hljs-string">"美国", <span class="hljs-string">"中国", <span class="hljs-string">"法国", <span class="hljs-string">"意大利", <span class="hljs-string">"韩国", <span class="hljs-string">"日本"] <span class="hljs-keyword">print(zip(lst1, lst1, lst3)) #<zip object at <span class="hljs-number">0x00000256CA6C7A88> <span class="hljs-keyword">for <span class="hljs-keyword">el in zip(lst1, lst2, lst3): <span class="hljs-keyword">print(<span class="hljs-keyword">el) # (<span class="hljs-number">1, <span class="hljs-string">"醉乡民谣", <span class="hljs-string">"美国") # (<span class="hljs-number">2, <span class="hljs-string">"驴得水", <span class="hljs-string">"中国") # (<span class="hljs-number">3, <span class="hljs-string">"放牛班的春天", <span class="hljs-string">"法国") # (<span class="hljs-number">4, <span class="hljs-string">"美丽人生", <span class="hljs-string">"意大利") # (<span class="hljs-number">5, <span class="hljs-string">"辩护人", <span class="hljs-string">"韩国") # (<span class="hljs-number">6, <span class="hljs-string">"被嫌弃的松子的一生", <span class="hljs-string">"日本") </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- fiter() 过滤 (lamda)
语法：fiter(function. Iterable)
function: 用来筛选的函数. 在filter中会自动的把iterable中的元素传递给function. 然后根据function返回的True或者False来判断是否保留留此项数据 , Iterable: 可迭代对象
<span class="hljs-function"><span class="hljs-keyword">def <span class="hljs-title">func<span class="hljs-params">(i): <span class="hljs-comment"># 判断奇数 <span class="hljs-keyword">return i % <span class="hljs-number">2 == <span class="hljs-number">1 lst = [<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5,<span class="hljs-number">6,<span class="hljs-number">7,<span class="hljs-number">8,<span class="hljs-number">9] l1 = filter(func, lst) <span class="hljs-comment">#l1是迭代器 print(l1) <span class="hljs-comment">#<filter object at 0x000001CE3CA98AC8> print(list(l1)) <span class="hljs-comment">#[1, 3, 5, 7, 9] </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
- map() 会根据提供的函数对指定序列列做映射(lamda)
语法 : map(function, iterable)
可以对可迭代对象中的每一个元素进行映射. 分别去执行 function
<span class="hljs-function"><span class="hljs-keyword">def <span class="hljs-title">f<span class="hljs-params">(i): <span class="hljs-keyword">return i lst = [<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5,<span class="hljs-number">6,<span class="hljs-number">7,] it = map(f, lst) <span class="hljs-comment"># 把可迭代对象中的每一个元素传递给前面的函数进行处理. 处理的结果会返回成迭代器print(list(it)) #[1, 2, 3, 4, 5, 6, 7] </span></span></span></span></span></span></span></span></span></span></span></span></span>
和作用域相关
- locals() 返回当前作用域中的名字
- globals() 返回全局作用域中的名字
<span class="hljs-function"><span class="hljs-keyword">def <span class="hljs-title">func<span class="hljs-params">():
a = <span class="hljs-number">10
print(locals()) <span class="hljs-comment"># 当前作用域中的内容
print(globals()) <span class="hljs-comment"># 全局作用域中的内容
print(<span class="hljs-string">"今天内容很多")
func()
<span class="hljs-comment"># {"a": 10}
<span class="hljs-comment"># {"__name__": "__main__", "__doc__": None, "__package__": None, "__loader__":
<span class="hljs-comment"># <_frozen_importlib_external.SourceFileLoader object at 0x0000026F8D566080>,
<span class="hljs-comment"># "__spec__": None, "__annotations__": {}, "__builtins__": <module "builtins"
<span class="hljs-comment"># (built-in)>, "__file__": "D:/pycharm/练习/week03/new14.py", "__cached__": None,
<span class="hljs-comment"># "func": <function func at 0x0000026F8D6B97B8>}
<span class="hljs-comment"># 今天内容很多
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
和迭代器生成器相关
- range() 生成数据
- next() 迭代器向下执行一次, 内部实际使用了__ next__()方法返回迭代器的下一个项目
- iter() 获取迭代器, 内部实际使用的是__ iter__()方法来获取迭代器
<span class="hljs-keyword">for i <span class="hljs-keyword">in range(<span class="hljs-number">15,-<span class="hljs-number">1,-<span class="hljs-number">5): <span class="hljs-built_in">print(i) <span class="hljs-comment"># 15 <span class="hljs-comment"># 10 <span class="hljs-comment"># 5 <span class="hljs-comment"># 0 lst = [<span class="hljs-number">1,<span class="hljs-number">2,<span class="hljs-number">3,<span class="hljs-number">4,<span class="hljs-number">5] <span class="hljs-literal">it = iter(lst) <span class="hljs-comment"># __iter__()获得迭代器 <span class="hljs-built_in">print(<span class="hljs-literal">it.__next__()) <span class="hljs-comment">#1 <span class="hljs-built_in">print(next(<span class="hljs-literal">it)) <span class="hljs-comment">#2 __next__() <span class="hljs-built_in">print(next(<span class="hljs-literal">it)) <span class="hljs-comment">#3 <span class="hljs-built_in">print(next(<span class="hljs-literal">it)) <span class="hljs-comment">#4 </span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
字符串类型代码的执行
- eval() 执行字符串类型的代码. 并返回最终结果
- exec() 执行字符串类型的代码
- compile() 将字符串类型的代码编码. 代码对象能够通过exec语句来执行或者eval()进行求值
s1 = input(<span class="hljs-string">"请输入a+b:") <span class="hljs-comment">#输入:8+9
print(eval(s1)) <span class="hljs-comment"># 17 可以动态的执行代码. 代码必须有返回值
s2 = <span class="hljs-string">"for i in range(5): print(i)"
a = exec(s2) <span class="hljs-comment"># exec 执行代码不返回任何内容
<span class="hljs-comment"># 0
<span class="hljs-comment"># 1
<span class="hljs-comment"># 2
<span class="hljs-comment"># 3
<span class="hljs-comment"># 4
print(a) <span class="hljs-comment">#None
<span class="hljs-comment"># 动态执行代码
exec(<span class="hljs-string">"""
def func():
print(" 我是周杰伦")
""" )
func() <span class="hljs-comment">#我是周杰伦
code1 = <span class="hljs-string">"for i in range(3): print(i)"
com = compile(code1, <span class="hljs-string">"", mode=<span class="hljs-string">"exec") <span class="hljs-comment"># compile并不会执行你的代码.只是编译
exec(com) <span class="hljs-comment"># 执行编译的结果
<span class="hljs-comment"># 0
<span class="hljs-comment"># 1
<span class="hljs-comment"># 2
code2 = <span class="hljs-string">"5+6+7"
com2 = compile(code2, <span class="hljs-string">"", mode=<span class="hljs-string">"eval")
print(eval(com2)) <span class="hljs-comment"># 18
code3 = <span class="hljs-string">"name = input("请输入你的名字:")" <span class="hljs-comment">#输入:hello
com3 = compile(code3, <span class="hljs-string">"", mode=<span class="hljs-string">"single")
exec(com3)
print(name) <span class="hljs-comment">#hello
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
输入输出
- print() : 打印输出
- input() : 获取用户输出的内容
print(<span class="hljs-string">"hello", <span class="hljs-string">"world", sep=<span class="hljs-string">"*", <span class="hljs-keyword">end=<span class="hljs-string">"@") <span class="hljs-meta"># sep:打印出的内容用什么连接,<span class="hljs-meta-keyword">end:以什么为结尾 <span class="hljs-meta">#hello*world@ </span></span></span></span></span></span></span></span>
内存相关
- hash() : 获取到对象的哈希值(int, str, bool, tuple). hash算法:(1) 目的是唯一性 (2) dict 查找效率非常高, hash表.用空间换的时间 比较耗费内存
s = <span class="hljs-string">"alex" <span class="hljs-built_in">print(<span class="hljs-built_in">hash(s)) <span class="hljs-comment">#-168324845050430382 lst = [1, 2, 3, 4, 5] <span class="hljs-built_in">print(<span class="hljs-built_in">hash(lst)) <span class="hljs-comment">#报错,列表是不可哈希的 id() : 获取到对象的内存地址 s = <span class="hljs-string">"alex" <span class="hljs-built_in">print(id(s)) <span class="hljs-comment">#2278345368944 </span></span></span></span></span></span></span></span></span></span>
文件操作相关
- open() : 用于打开一个文件, 创建一个文件句柄
<span class="hljs-keyword">f = <span class="hljs-keyword">open(<span class="hljs-string">"file",<span class="hljs-keyword">mode=<span class="hljs-string">"r",encoding=<span class="hljs-string">"utf-8") <span class="hljs-keyword">f.<span class="hljs-keyword">read() <span class="hljs-keyword">f.<span class="hljs-keyword">close() </span></span></span></span></span></span></span></span></span></span>
模块相关
__ import__() : 用于动态加载类和函数
<span class="hljs-comment"># 让用户输入一个要导入的模块 <span class="hljs-attribute">import os name = input(<span class="hljs-string">"请输入你要导入的模块:") __import__(name) <span class="hljs-comment"># 可以动态导入模块 </span></span></span></span>
帮 助
- help() : 函数用于查看函数或模块用途的详细说明
<span class="hljs-built_in">print(<span class="hljs-built_in">help(str)) <span class="hljs-comment">#查看字符串的用途 </span></span></span>
调用相关
- callable() : 用于检查一个对象是否是可调用的. 如果返回True, object有可能调用失败, 但如果返回False. 那调用绝对不会成功
a = <span class="hljs-number">10 print(callable(a)) <span class="hljs-comment">#False 变量a不能被调用 <span class="hljs-comment"># <span class="hljs-function"><span class="hljs-keyword">def <span class="hljs-title">f<span class="hljs-params">(): print(<span class="hljs-string">"hello") print(callable(f)) <span class="hljs-comment"># True 函数是可以被调用的 </span></span></span></span></span></span></span></span></span>
查看内置属性
- dir() : 查看对象的内置属性, 访问的是对象中的__dir__()方法
<span class="hljs-built_in">print(dir(tuple)) <span class="hljs-comment">#查看元组的方法 </span></span>
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转载请注明原文链接：这68个Python内置函数，建议你吃透！
转载请注明原文链接：这68个Python内置函数，建议你吃透！
