Python学习 day2
name = "xiao hua" print(name.capitalize()) #首字母大写 >>>Xiao hua print(name.count("w")) #数个数 >>>0 print(name.center(30,"-")) #居中 >>>-----------xiao hua----------- print(name.encode()) >>>b'xiao hua' print(name.endswith("ua")) #判断以什么结尾是真还是假 >>>True print(name.find("hua")) #查找 >>>5 name = "my name is {name},my age is {year} old." print(name.format(name ="xiao hua",year = 21)) #格式化 >>>my name is xiao hua,my age is 21 old. print(name.format_map({"name":"xiao hua","year":21})) #与format类似,只不过用的是字典方式 >>>my name is xiao hua,my age is 21 old. print("abAc012".isalnum()) #检测是否为英文字符以及数字(小数点也不行),特殊字符不行 >>>True print("abAd".isalpha()) #检测是否为纯英文字符 >>>True print("1.2".isdigit()) #判断是否为整数 >>>False print("bA".islower()) #是否为小写 >>>False print("bA".isupper()) #是否大写 >>>False print(" ".isspace()) #是否为空格 >>>True print("My name is wang".istitle()) #是否为标题(My Name Is Wang为真) >>>False name = "Leonia" print(name.ljust(30,"*")) #字符串放左边,30个空用*排满,类比center >>>Leonia************************ print(name.rjust(30,"*")) #字符串放右边 >>>************************Leonia print("WaNg".lower()) #把大写变小写 >>>wang print("WaNg".upper()) #把小写变大写 >>>WANG print(" wan g ".lstrip()) #去除左边空格 >>>wan g print(" wan g ".rstrip()) #去除右边空格 >>>wan g print(" wan g ".strip()) #去除两边空格 >>>wan g a = str.maketrans("abcedfg","1234567") print("wang".translate(a)) #类似简单加密 >>>w1n7 print("wang".replace("a","e")) #替换 >>>weng print("wangwenwing".replace("w","b",3)) #3为替换3个 >>>bangbenbing print("leonia xiao hua".split("i")) #改成列表,并将所选字符替换成空格间断开 ["leon","a x","ao hua"] print("waNg".swapcase()) #大小写互换 >>>WAnG print("wang".title()) #变标题 >>>Wang
字典的使用方法
key:value 字典是无序的,列表是有序的
fruit = { "001":"苹果", "002":"香蕉", "003":"梨", } print(fruit["001"]) #查找 >>>苹果 print(fruit.get("101")) #如果所查找数据不存在,就运行为None;如果存在,则显示内容 >>>None print("009" in fruit) #检测所查询数据在字典中是否存在 >>>False fruit["004"] = "葡萄" #增加 print(fruit) >>>{'001': '苹果', '002': '香蕉', '003': '梨', '004': '葡萄'} fruit["002"] = "西瓜" #替换 print(fruit) >>>{'001': '苹果', '002': '西瓜', '003': '梨', '004': '葡萄'} del fruit["003"] #删除 print(fruit) >>>{'001': '苹果', '002': '西瓜', '004': '葡萄'} fruit.pop("002") #删除 print(fruit) >>>{'001': '苹果', '003': '梨', '004': '葡萄'} fruit.popitem() #随机删除 print(fruit) >>>{'001': '苹果', '002': '西瓜', '003': '梨'}
字典的多级嵌套
map = { "山东":{"010":"济南","011":"聊城","012":"德州"}, "安徽":{"020":"宿州","021":"砀山","022":"合肥"}, "陕西":{"030":"西安","031":"杨凌","032":"宝鸡"}, } print(map.values()) #打印所有的values >>>dict_values([{'010': '济南', '011': '聊城', '012': '德州'}, {'020': '宿州', '021': '砀山', '022': '合肥'}, {'030': '西安', '031': '杨凌', '032': '宝鸡'}]) print(map.keys()) #打印所有的keys >>>dict_keys(['山东', '安徽', '陕西']) print(map.setdefault("河北",{"002":"东阿"})) ##去水果里取对应的值,若能取到,返回;若取不到,新建值并对应后面字典的内容 >>>{'002': '东阿'} map2 = { "山东": {"010": "济南", "011": "东阿", "012": "德州"}, "安徽": {"020": "宿州", "021": "砀山", "022": "合肥"}, "重庆": {"030": "妹子", "031": "火锅", "032": "串串"}, } map.update(map2) print(map) #合并两个字典,重叠部分更新,其余部分加入 >>>{'山东': {'010': '济南', '011': '东阿', '012': '德州'}, '安徽': {'020': '宿州', '021': '砀山', '022': '合肥'}, '陕西': {'030': '西安', '031': '杨凌', '032': '宝鸡'}, '河北': {'002': '东阿'}, '重庆': {'030': '妹子', '031': '火锅', '032': '串串'}} print(map.items()) #字典变列表 >>>dict_items([('山东', {'010': '济南', '011': '东阿', '012': '德州'}), ('安徽', {'020': '宿州', '021': '砀山', '022': '合肥'}), ('陕西', {'030': '西安', '031': '杨凌', '032': '宝鸡'}), ('河北', {'002': '东阿'}), ('重庆', {'030': '妹子', '031': '火锅', '032': '串串'})]) a = dict.fromkeys([1,2,3],["pig","dog","cat"]) print(a) >>>{1: ['pig', 'dog', 'cat'], 2: ['pig', 'dog', 'cat'], 3: ['pig', 'dog', 'cat']} a[1][1] = "chicken" print(a) ##列表变字典,相当于浅copy >>>{1: ['pig', 'chicken', 'cat'], 2: ['pig', 'chicken', 'cat'], 3: ['pig', 'chicken', 'cat']}