Python3 f string alternativ in Python2

Question

Mostly i work with Python3. There can i write this

print(f"the answer is {21 + 21} !")

output: the answer is 42 ! But in Python 2 f strings not exist. So is this the best way ?

print("the answer is " + str(21 + 21) + "!")

Answer 1

使用format ：

print("the answer is {} !".format(21 + 21))

Answer 2

There are two ways

>>> "The number is %d" % (21+21)
'The number is 42'
>>> "The number is {}".format(21+21)
'The number is 42'

Answer 3

Actually you can use .format() method for readabilty and it is the where f string comes from.

You can use:

print("the answer is {}!".format(21+21))

Answer 4

You can use the fstring library

pip install fstring

>>> from fstring import fstring as f
>>> a = 4
>>> b = 5
>>> f('hello result is {a+b}')
u'hello result is 9'