Python简单代码积累

# 写一个函数，实现通过交换字典中的Key和Value生成新的一个字典
如字典a = {"name":"rotate", "age":29, "score":88}，经过交换后变成{"rotate":"name", 29:"age", 88:"score"}。

def pDict():
    a = {"name":"rotate", "age":29, "score":88}
    b = {v:k for k,v in a.items()}
    print(b)
pDict()

输出结果：{'rotate': 'name', 29: 'age', 88: 'score'}

 

#列表 plist = [734, 8465, 94, 4345, 653, 266, 665, 5]，写一个函数，按照如下的字符串形式 "94846573466565354345266" 输出。

def list_sort(plist):
    list = [str(x) for x in plist]           #将数值列表转换成字符串列表  ['734', '8465', '94', '4345', '653', '266', '665', '5']
    list.sort(reverse=True)                  #sort排序再反排序   ['94', '8465', '734', '665', '653', '5', '4345', '266']

    list1 = ''.join(list)                    #List列表转为Str字符串 
    return list1 
    plist = [734, 8465, 94, 4345, 653, 266, 665, 5] 
result=list_sort(plist) print(result)

输出结果：94846573466565354345266

#找出字符串中出现的第一个不重复的字符.

#coding=utf-8
def findFirstCharacter(pstr):
    for i in range(len(pstr)):
        if pstr.index(pstr[i]) == pstr.rindex(pstr[i]):
            return pstr[i]
    return None

pstr = "djkljjkjkjlda"
result = findFirstCharacter(pstr)
print(result)

输出结果：a　　

# 判断字符串是否是一个ip地址（ipv4地址，如 192.168.1.1）

#coding=utf-8
def isIpAddress(ip_address):

    if not isinstance(ip_address,str):
        print("ilegal input,please enter ip again")
　　　　　return False
    if ip_address.count('.') != 3:
        return False
    else:
        ip = ip_address.split('.')
        for i in ip:
            try:
                one_ip = int(i)

                if one_ip>=0 and one_ip <=255:
                   pass
                else:                                              
                    print(one_ip)
                    return False
            except:
                print( "{0} is not a number.".format(i))
                return False
        return True

                  
if __name__ == "__main__":

    while True:
        myIp = input("please enter ip： ")
        if isIpAddress(myIp):
            print("{0} is a legal ip".format(myIp))
        else:
            print("this is not a legal ip")

#统计字符串中的字符出现的次数

pstr = "hdkfjowfojlkjal"
pDict = {}
for s in pstr:
    PDict[s] = pstr.count(s)
print(PDict)

　

 #删除重复的二维列表

二维列表中，里面元素能用元组则用元组