How to print like printf in Python3?

In Python2, print was a keyword which introduced a statement:

print "Hi"

In Python3, print is a function which may be invoked:

print ("Hi")

In both versions, % is an operator which requires a string on the left-hand side and a value or a tuple of values or a mapping object (like dict) on the right-hand side.

So, your line ought to look like this:

print("a=%d,b=%d" % (f(x,n),g(x,n)))

Also, the recommendation for Python3 and newer is to use {}-style formatting instead of %-style formatting:

print('a={:d}, b={:d}'.format(f(x,n),g(x,n)))

Python 3.6 introduces yet another string-formatting paradigm: f-strings.

print(f'a={f(x,n):d}, b={g(x,n):d}')

The most recommended way to do is to use format method. Read more about it here

a, b = 1, 2

print("a={0},b={1}".format(a, b))

Python 3.6 introduced f-strings for inline interpolation. What's even nicer is it extended the syntax to also allow format specifiers with interpolation. Something I've been working on while I googled this (and came across this old question!):

print(f'{account:40s} ({ratio:3.2f}) -> AUD {splitAmount}')

PEP 498 has the details. And... it sorted my pet peeve with format specifiers in other langs -- allows for specifiers that themselves can be expressions! Yay! See: Format Specifiers.

Simple printf() function from O'Reilly's Python Cookbook.

import sys
def printf(format, *args):
    sys.stdout.write(format % args)

Example output:

i = 7
pi = 3.14159265359
printf("hi there, i=%d, pi=%.2f\n", i, pi)
# hi there, i=7, pi=3.14