[Python知识库]python字符串相关操作

question1：运算优先级问题

1.乘除优先加减

2.位运算 == 算数运算 > 比较运算 > 赋值运算 > 逻辑运算

?

a,b,x,y = 10, 20, 30, 40

d = (5 + 10 * x)/5 -13 * (y - 1) * (a + b)/x + 9*(5 / x + (12 + x)/y)

print(d)

question2：input()的使用

从控制台输入用户的月薪，进行运算计算出年薪。打印输出用户的年薪

notes：input()获得的为string，要转为int

month_salary = input()

month_salary = int(month_salary)

year_salary = 12 * month_salary 

print(year_salary)

questions3：字符串的倒序输出

str = 'to be or not to be'
len_str = len(str)
str_reverse = str[::-1]
print(str_reverse)

questions4：输出指定位置字符

notes：第一个位置为0

str = 'sxtsxtsxtsxtsxt'

'''
place = 0 3 6 9 12
'''

str_s = str[0:len(str):3]

print(str_s)

question5：is 的含义和字符串驻留机制

a = "abd_33"
b = "adb_33"
c = "dd#"
d = "dd#"

e = a is b
f = c is d
print(e,f)

a is b ture

c is d false

a is b，a b满足python的字符串驻留机制，所以ture

c is d，c d不满足，false

驻留机制出发条件：字符串仅包含下划线(_)、字母和数字

question6：format使用

c = "名字是{name},年龄是{age}"

print(c)

print(c.format(age=19,name='高淇'))

'''

>>>
    名字是{name},年龄是{age}
    名字是高淇,年龄是19

'''