格式化字符串总体上有三种方式四种写法
直接上代码：
str_t1 = 'it is a test from %s, I am %d years old'
str_t2 = 'it is a test from %(name)s, I am %(age)d years old'
str_t3 = 'it is a test from {name}, I am {age} years old'
str_1 = str_t1 % ('quan', 18)
str_2 = str_t2 % {'name': 'quan', 'age': 18}
str_3 = str_t3.format(**{'name': 'quan', 'age': 18})
str_4 = str_t3.format(name='quan', age=18)
print str_1
print str_2
print str_3
print str_4
结果：
it is a test from quan, I am 18 years old
it is a test from quan, I am 18 years old
it is a test from quan, I am 18 years old
it is a test from quan, I am 18 years old
————————————————