• python开发的IDLE


    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()

      

     2.3列表-list

     通过list类创建的对象,如:

    li=[1,12,90,['李明',"Succ",78],"alex","age"]
    print(li[3:-1])       #切片,切片的结果也是列表
    for item in li:       #for循环取值
        print(item)

    列表可以被修改、删除:

    li=[1,12,90,['李明',"Succ",78],"alex","age"]
    li[1]=120       #修改
    print(li)
    
    del li[2]         #删除
    print(li)

    列表的in操作:

    li=[1,12,90,['李明',"Succ",78],"alex","age"]
    v=li[3][0][1]
    print(v)

    转换:
    (1)字符串转换为列表:

    li=list("avaswmdqwklenf")
    print(li)

    (2)列表转换为字符串:

    #用for循环一个一个处理:既有数字又有字符串
    a=["success",1234]
    for i in (str(a)):
        print(i)
    #直接用join方法:列表中的元素只有字符串
    a=["success","1234"]
    v=" ".join(a)
    print(v)

    列表的追加、删除、复制

    li = [1, 12, 90, ['李明', "Succ", 78], "alex", "age", 90, 90]
    li.append(5)
    print(li)
    
    v=li.clear()
    print(v)
    
    li.copy()
    print(li)

    计算列表中元素出现的次数:

    li = [1, 12, 90, ['李明', "Succ", 78], "alex", "age", 90, 90]
    v=li.count(90)
    print(v)
    li = [1, 12, 90, ['李明', "Succ", 78], "alex", "age", 90, 90]
    
    v=li.index(90)                 #寻找值
    print(v)
    
    li.extend([9988,"liing",])  #执行了循环
    print(li)
    
    li.extend("liing",)
    print(li)
    
    li.insert(2,99)             #在指定索引位置插入
    print(li)
    
    v=li.pop(3)                #默认情况下,删除某一值,并获取相关值
    print(li)
    print(v)
    
    li.remove(12)            #删除列表中的指定值,左边优先
    print(li)

    2.4元祖-tuple

    元组:元素不可修改,不能增加或删除,一般写元组在最后加一个‘,’号。

    tu = (11, 'alex', (11, 22), [(33, 44)], True, 45, 11,)
    
    # 索引取值
    v=tu[3]
    print(v)
    
    # 切片
    v=tu[0:3]
    print(v)
    
    # for 循环
    for item in tu:
        print(item)
    
    # 元组有序
    v=tu[3][0][1]
    print(v)
    
    # count:获取指定元素在元组中出现的次数
    v=tu.count(11)
    print(v)
    
    # index索引
    v=tu.index('alex')
    print(v)
    View Code

    2.5字典-dict

    # 字典:dict
    
    # 基本结构
    info={
          "k1":"v1",   # 键值对
          "k2":"v2",
    }
    
    # 字典中的value可以是任意值
    info = {
        "k1": 18,
        "k2": True,
        "k3": [
            11,
            [],
            (),
            22,
            33,
            {
                "kk1": "vv1",
                "kk2": "vv2",
                "kk3": (11,22),
            }
        ],
        "k4": (11, 22, 33, 44),
    }
    v=info["k3"][5]["kk3"][0]
    print(v)
    
    # 列表、字典不能作为字典的key,布尔值会与(0,1)重复
    info = {
        "k1": 18,
        1: 123,
        True: [
            11,
            [],
            (),
            22,
            33,
            {
                "kk1": "vv1",
                "kk2": "vv2",
                "kk3": (11, 22),
            }
        ],
        "k4": (11, 22, 33, 44),
    }
    print(info)
    View Code

    字典中的for循环

    # for循环
    info = {
        "k1": 18,
         3: 123,
        True: [
            11,
            [],
            (),
            22,
            33,
            {
                "kk1": "vv1",
                "kk2": "vv2",
                "kk3": (11,22),
            }
        ],
        "k4": (11, 22, 33, 44),
    }
    for item in info:     #默认关键词
        print(item)
    
    for item in info.values():
        print(item)
    
    for k,v in info.items():
        print(k,v)
    View Code
    # 判断
    dic={
        "k1":"v1"
    }
    v="k" in dic    #判断k是否是关键词
    print(v)
    
    v="v1" in dic.values()
    print(v)
    
    # fromkeys:根据序列,创建字典,指定统一的值
    dic = {
        "k1": "v1"
    }
    v = dic.fromkeys(["k1", 123, "99"])
    print(v)
    v = dic.fromkeys(["k1", 123, "99"], 123)
    print(v)
    
    # get:根据key获取值,key不存在是,可指定默认值
    v=dic.get("k1")
    print(v)
    
    v=dic.get("k111",111)
    print(v)
    
    # pop指定某个ki删除
    v=dic.pop("k1")
    print(dic,v)
    
    v=dic.pop("k111",90)
    print(dic,v)
    
    # popitem:随机删除
    dic = {
        "k1": "v1",
        "k2": "v2",
        "k3": "v3",
    }
    v=dic.popitem()
    print(dic,v)
    k, v = dic.popitem()
    print(dic, k, v)
    
    # setdefault:设置值,已存在,不设置,获取当前key对应的值;不存在,设置
    v=dic.setdefault('k1','123')
    print(dic,v)
    v=dic.setdefault('k11','123')
    print(dic,v)
    
    # update
    dic.update(k1=123,k3=456,k5="adcs")
    print(dic)
    View Code


     

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  • 原文地址:https://www.cnblogs.com/changzhendong/p/10988295.html
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