01月22日【Python3 基础知识】
- 2020 年 1 月 3 日
- 筆記
01月22日【Python3 基础知识】
2.4 计算器 2.5 tuple操作 2.6 dict 2.7 其他常用操作
2.4 计算器
def add(string): total = 0 numbers = [] numbers += string.split("+") for num in numbers: total += int(num.strip()) print("{0} = {1}".format(string, total)) # def reduce(string): result = 0 numbers = [] numbers += string.split("-") result = int(numbers[0].strip()) numbers.pop(0) for num in numbers: result -= int(num.strip()) print("{0} = {1}".format(string, result)) # def ride(string): total = 1 numbers = [] numbers += string.split("*") for num in numbers: total *= int(num.strip()) print("{0} = {1}".format(string, total)) # def division(string): result = 0 numbers = [] numbers += string.split("/") result = int(numbers[0].strip()) numbers.pop(0) for num in numbers: result /= int(num.strip()) print("{0} = {1}".format(string, result)) if __name__ == '__main__': print("##############################################") print("1: +法") print("2: -法") print("3: *法") print("4: /法") method = input("请选择: ") string = input("请输入:") if method == "1": add(string) elif method == "2": reduce(string) elif method == "3": ride(string) elif method == "4": division(string) else: print("输入错误") print("##############################################")
2.5 tuple操作
# 元组的元素不能修改 t = ('a', 'b', 3, 'b') print(t) print(t[0]) # 按下标输出元素 # index: 按元素输出下标 print(t.index('b')) # 默认左往右 print(t.index('b', -1)) # 倒序查找 # count:统计字符个数 print(t.count('b'))
2.6 dict
# 字典的定义: d1 = dict(name = 'long', age = 30) d2 = {'id':101, 'name':'longlong'} d3 = dict([('name', 'long'), ('age', 20)]) print(d1) print(d2) print(d3) # 方法 # get(key): 根据key获取value # setdefault: 根据key获取value,如果key不存在,可以设定默认的value print((d1.get('name'))) print(d1.setdefault('dizhi', 'guangxi')) # print(d1.keys()) print(d1.values()) # for x, y in d1.items(): print("{0}:{1}".format(x, y)) # update: 根据key更新valye;如果没有key则会添加该键值对 print(d1) d1.update(d2) print(d1) # pop:根据key弹出value print(d3.pop('name')) print(d3)
2.7 其他常用操作
# help： 方法解释 a = '123' help(a.count) # dir: 查看有什么方法可用 print(dir(a)) ## type: 查看变量类型 print(type(a)) # len： 获取长度 print(len(a)) # isinstance: 判断变量是否某类型 print(isinstance(a, str))
