Python 字符串占位符与.format格式化的用法

共三种方法可以实现
直接上代码，一看就能懂：

my_name = 'Richard'
age = 22
salary = int(input('please input your salary:'))

# method 1 占位符,%s表示只能接受string, %d代表只能接受数字，所以上边salary接受的input输入，需要强转为int类型
res1 = 'res1: My name is %s ,I\'m %d years old, my salary is %d'%(my_name,age,salary)
print(res1)

# method 2 .format的用法1，需要用{n}作占位符，占位符从0开始
res2 = 'res2: My name is {0} ,I\'m {1} years old, my salary is {2}'.format(my_name,age,salary)
print(res2)

# method 3 .format的用法2，需要用{alias}作占位符
res3 = 'res3: My name is {_name} ,I\'m {_age} years old, my salary is {_salary}'.format(_name=my_name,_age=age,_salary=salary)
print(res3)

运行结果：

please input your salary:22222
res1: My name is Richard ,I'm 22 years old, my salary is 22222
res2: My name is Richard ,I'm 22 years old, my salary is 22222
res3: My name is Richard ,I'm 22 years old, my salary is 22222