2.4 計算器
2.5 tuple操作
2.6 dict
2.7 其他常用操作

2.4 計算器

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("請選擇: ")
    string = input("請輸入:")
    if method == "1":
        add(string)
    elif method == "2":
        reduce(string)
    elif method == "3":
        ride(string)
    elif method == "4":
        division(string)
    else:
        print("輸入錯誤")
    print("##############################################")
 

2.5 tuple操作

# 元組的元素不能修改
t = (‘a‘, ‘b‘, 3, ‘b‘)
print(t)
print(t[0]) # 按下標輸出元素
# index: 按元素輸出下標
print(t.index(‘b‘))     # 默認左往右
print(t.index(‘b‘, -1)) # 倒序查找
# count:統計字符個數
print(t.count(‘b‘))

2.6 dict

# 字典的定義:
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): 根據key獲取value
# setdefault: 根據key獲取value,如果key不存在,可以設定默認的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: 根據key更新valye;如果沒有key則會添加該鍵值對
print(d1)
d1.update(d2)
print(d1)
# pop:根據key彈出value
print(d3.pop(‘name‘))
print(d3)
 

2.7 其他常用操作

# help： 方法解釋
a = ‘123‘
help(a.count)
# dir: 查看有什麽方法可用
print(dir(a))
## type:  查看變量類型
print(type(a))
# len： 獲取長度
print(len(a))
# isinstance: 判斷變量是否某類型
print(isinstance(a, str))

01月22日【Python3 基礎知識】