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<p><span style="font-size:16px;color:#000000;"><strong>1、内置函数</strong></span><br><span style="color:#000000;"> int('123')</span><br><span style="color:#000000;"> float()</span><br><span style="color:#000000;"> string()</span><br><span style="color:#000000;"> tuple()</span><br><span style="color:#000000;"> set()</span><br><span style="color:#000000;"> dict(name='zdd',age=18)</span><br><span style="color:#000000;"> type()#查看类型</span><br><span style="color:#000000;"> len()#看长度,其实是元素的个数</span><br><span style="color:#000000;"> id()#看内存地址</span><br><span style="color:#000000;"> print(sorted([1,7,6,4,9,8]))#排序,不改变原来的list,从小到大</span><br><span style="color:#000000;"> sorted([1,7,6,4,9,8],reverse=True)#倒叙排列</span><br><span style="color:#000000;"> print(list(reversed(sorted([1,7,6,4,9,8]))))#反转,从大到小,reversed()打印的是一个内存地址</span><br><span style="color:#000000;"> isinstance(b,dict)#判断什么类型,返回true或者false</span><br><span style="color:#000000;"> print(all([1,2,3,4]))#判断可迭代的对象里面的值是否都为真 </span><br><span style="color:#000000;"> print(any([0,1,2,3,4]))#判断可迭代的对象里面的值是否有一个为真</span><br><span style="color:#000000;"> print(bin(10))#十进制转二进制</span><br><span style="color:#000000;"> print(bool('s'))#把一个对象转换成布尔类型</span></p>
<p><span style="color:#000000;"> print(bytearray('abcde', encoding='utf-8')) # 把字符串变成一个可修改的bytes</span><br><span style="color:#000000;"> print(callable(my_type)) # 判断传入的对象是否可调用</span><br><span style="color:#000000;"> print(chr(10)) # 打印数字对应的ascii</span><br><span style="color:#000000;"> print(ord('b')) # 打印字符串对应的ascii码</span><br><span style="color:#000000;"> print(dict(a=1, b=2)) # 转换字典</span><br><span style="color:#000000;"> print(dir(1))#打印传入对象的可调用方法</span><br><span style="color:#000000;"> print(exec('def a():print("蓝夏")'))#执行python代码,只能执行简单的,定义数据类型和运算</span></p>
<p><span style="color:#000000;"> def calc(a):</span><br><span style="color:#000000;"> if a%2==0:</span><br><span style="color:#000000;"> return True</span><br><span style="color:#000000;"> res=filter(calc,[12,3,5,6,7])</span><br><span style="color:#000000;"> res=map(calc,[12,3,5,6,7]))</span><br><span style="color:#000000;"> print(res)#打印的是内存地址<br> print(list(filter(calc,[12,3,5,6,7])))#挨个把后面的元素传入到前面的函数调用,如果函数处理完返回true,就把这个元素保存下来,打印出[12, 6],只需要传函数名,不需要调用</span><br><span style="color:#000000;"> print(list(map(calc,[12,3,5,6,7])))#替你循环调用这个函数,把函数运算完的结果返回回来,打印出[True, None, None, True, None],只需要传函数名,不需要调用<br></span></p>
<p><span style="color:#000000;"> print(hex(111))#数字转成16进制</span><br><span style="color:#000000;"> print(sum([1,2,3,4,5]))#求和</span><br><span style="color:#000000;"> print(max(111,12))#取最大值</span><br><span style="color:#000000;"> print(oct(111))#把数字转换成8进制</span><br><span style="color:#000000;"> print(round(11.1111,2))#取几位小数</span></p>
<p><span style="font-size:14px;"><strong><span style="color:#000000;"> <span style="color:#000000;">例子1:<span style="color:#000000;">判断输入参数的<span style="font-family:'Microsoft YaHei';">类型</span></span></span></span></strong></span></p>
<p><span style="font-family:arial, helvetica, sans-serif;"><span style="color:#000000;"><span style="font-size:14px;"> </span></span><span style="color:#000000;">def my_type(var):</span></span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> if type(var)==list:</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> print('这个是list')</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> elif type(var)==<span style="font-size:14px;">dic</span>t:</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> print('这个是字典')</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> elif type(var)==str:</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> print('这个<span style="font-size:14px;">是字</span>符串')</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> elif type(var)==int:</span><br><span style="color:#000000;font-family:arial, helvetica, sans-serif;"> |
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