python笔记

1. 读取文件

fin = open("D:\tools\log\words.txt")
    for fi in fin:
        print(fi.strip())　　#去掉空格

2. 字符串处理

testStr = "asdfjlsj"
    print(testStr[2:4])　　#字符串截取
    print(testStr[5:])
    print(testStr[6])
    print(len(testStr))
　　 print(testStr.isupper())

3. 列表操作（数组）

arr = [1,"323", 2.22, [3,"dsljf"]]
    arr[1] = 30
    print(arr[1])
    print(2.22 in arr)
    for ar in arr:
        print(type(ar))
        print(ar)
    print(arr[1:3]) #列表拆分
    arr.append("hello") #追加数据
    print(arr)
    
    t1 = [1,2,3]
    t2 = [4,5]
    t1.extend(t2)   #列表添加
    print(t1)
    print(sum(t1))
    
    t1.pop(1)   #通过下标删除元素
    print(t1)
    t1.remove(4)    #通过值删除元素
    print(t1)
    s = "we332dfj"
    print(list(s))  #字符串转列表
    
    sp = "-"
    arr1 = ["dsf","3r3", "323jj"]
    s1 = sp.join(arr1)  #列表转字符串
    print(s1)

4. 字典

eng = dict()    #空字典
    eng["a"] = "abc"
    print(eng["a"])
    
    eng2 = {"a":"abc", "b":"bcd"}
    print(eng2)
    print(len(eng2))
    print("a" in eng2)
    print(eng2.values())
    
    eng3 = "abcajjkedabedd"
    eng4 = dict()
    for st in eng3:
        if st in eng4:
            eng4[st] += 1
        else:
            eng4[st] = 1
    
    print(eng4) 
    
    t1 = "234234@qq.com"
    name,url = t1.split("@")
    print(name + " " + url)
    
    t = divmod(7, 3)    #同时计算出商和余数   也可以使用  quot, rem = divmod(7, 3)  来接收结果
    print(t)
    print(max(t) + min(t))   #获取元祖最大值和最小值
    
    a = "abc"
    b = [1,2,3]
    c = zip(a,b)    #拉链操作 结果：('a', 1)('b', 2)('c', 3)
    for d in c:
        print(d)
        
    for index, element in enumerate("asd234"):  #enumerate函数遍历下标和值
        print("index:"+str(index) + " element:"+element)
        
    d = {"a":1, "b":2}  #字典转元祖列表
    print(items(d))     #运行结果： [('a', 1), ('b', 2)]
    
    for key, value in d.items():
        print(key + " "+ str(value))
        
    t = [("a",1),("b",2)]
    print(dict(t))  #元祖的列表转字典
    
    print(random . randint (5 , 10))    #返回一个 5-10 之间的随机数
    
    t2 = [2,3,5]
    print(random.choice(t2))

5. os 操作文件

#遍历获取目录下的所有文件，包括子文件
def abc(dirName):
    for name in listdir(dirName):
        path = os.path.join(dirName, name)  #获取全路径（接收一个目录 和 文件名，并把它们合并成一个完整路径）
        
        if os.path.isfile(path):
            print(path)
        else:
            abc(path)

print(os.path.exists(dirName))  #路径是否存在
    print(os.path.isfile(dirName))  
    print(os.path.isdir(dirName))
    print(os.getcwd())  #获取当前文件所在目录
    try:
        fin = os.open(dirName)
    except:
        print("some exception!!!")