格式化输出
程序中经常会有这样场景： 要求用户输入信息，然后打印成固定的格式 比如： name1 = '小李子' name2 = '小橙子' num = 123.123456 age = 25 age1 = 34 age2 = 55 #占位符:%s,%d,%f >>> res = 'my name is %.2f' >>> res = 'my name is %s' >>> print(res % name1) my name is 小李子 >>> print(res % name2) my name is 小橙子 >>> print(res) my name is %s >>> res = 'my name is %s, my age is %s' % (name1,age) >>> print(res) my name is 小李子, my age is 25 >>> res = 'my num is %d' >>> print(res % num) my num is 123 >>> res = 'my num is %s' >>> print(res % num) my num is 123.123456 >>> res = 'my num is %f' >>> print(res % num) my num is 123.123456 >>> res = 'my num is