python基础

1.运算符:

                数字运算符:+、-、*、/、% 、//

                整体注释:ctrl+?,   判断条件:in、  not  in

                字符串:

                布尔值:ture (真)     false(假)

                逻辑运算:and   or    not

                赋值运算:如count=count+1等于count+=1,其他同理可得。

     结果是值的有:算数运算和赋值运算

     结果是布尔值的有:比较运算、逻辑运算、成员运算

2.基本数据类型:

        2.1数字:a1=123;a2=2341

              数字:int,所有的功能都在int里,python3里int类型无范围,python2里有整形和长整形

         2.1.1  -int:    a=“123”

                                b=int(a): 将字符串转换为数字。注意:a=‘123a’不能转换

                   如果想要查看是什么类型,用“type”; print(type(a),a)

                              num='0011'

                              v=int(num,base=16):将num以16进制转换

                              print(v)

          2.2.2  -bit_length:

                               #:当前数字的二进制,至少用n为表示

                               age=8

                               r=(age).bit_length()

          2.2字符串-str: def format:格式化,将字符串中的占位符替换为指定的值

                                          format_map:{"name":'    ',  "a":   19}

                                          find:从开始往后找,找到第一个,写出其位置

                                          index :找不到,报错。

                                          isalnum: 判断字符串中是否只包含:字母、数字 

                                          expandtabs:     n表示换行, t表示空格

                                          startswith:找变量的开始

                                         endswith:找变量的尾部

                                         isalpha:判断字母、汉字

                                         isdecimal、isdigit:判断当前输入的是否为数字,isdigit可判定特殊数字:②等。

                                         swapcase:大小写字母转化

                                         isidentifier:判别字母、数字、下划线

                                        isnumeric:判别是否是数字

                                        isprintable:判断是否存在不可显示的字符

                                        isspace:判断是否全部是空格

                                        istitle:判断是否为标题(标题的每个首字母大写)

                                        join:将字符串中的每个元素按照指定分隔符进行拼接

                                        islower:判断是否全部是小写

                                        isupper:判断是否全部是大写

                                        lstrip:去左空白,移除指定字符,有限最多匹配

                                        rstrip:去右空白,移除指定字符,有限最多匹配

                                         strip:去除左右空白

                                        translate:替换

                                       partition、repartition:分割

                                       split、rsplit:分割

                                       splitliness:只能依据True/False:是否保留换行

                                       replace:替代

         

                     

原文地址:https://www.cnblogs.com/changzhendong/p/10993966.html