python string formatting

You can do two ways of string formatting in Python. The most easy way is to use f-strings or formatted strings. The other way is similar to the printf function in the C programming language.

The printf way:

>>> print('this is %d %s pet' % (1,'hungry'))
this is 1 hungry pet
>>> 

The f-strings way (has an f in front of the string):

>>> n = 1
>>> s = 'hungry'
>>> print(f'this is {n} {s} pet')
this is 1 hungry pet
>>> 

Obviously the f-strings way is better, but you may find code with the old C style way. So in the C printf way, what is this %?

It lets you output a type of variable. For a string %s, for a number %d.

>>> 
>>> name = 'goofy'
>>> 'my name is %s ' % name
'my name is goofy '
>>> 'that will be %d dollars please' % 5
'that will be 5 dollars please'
>>> 

So you know %d and %s` string formatting codes, but there are others.

>>> a = 678
>>> print('integer %i is a number' % a)
integer 678 is a number
>>> 

If you want a float, change it:

>>> a = 1.23456
>>> print('float has value of %f ' %a)
float has value of 1.234560 
>>> 

You can use multiple variables in a string:

>>> name = 'goofy'
>>> age = 50
>>> print('I am %s and I am %d years old' % (name,age))
I am goofy and I am 50 years old
>>> 

Read more:

• Python formatted strings
• Python string examples