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。

python开发的IDLE
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

python开发的IDLE
# 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

python开发的IDLE
# 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 python开发的IDLE
# 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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