如何在Python中组合变量以形成函数？

Question

ypos = 1
ypos2 = ypos-1
xpos = 1
xpos2 = 2

Using these variables, that are changed each time the code loops, how do I get it to print the result below?

=B(ypos)-B(ypos2)

Every time the code loops the ypos increases by one and therefore the ypos2 increases by one

so as the code loops the results should be 1) B1-B0 2) B2-B1 3) B3-B2 etc.

Any help is much appreciated, and if you don't understand the question let me know, I wasn't quite sure how to explain it.(PS I am using python2.7)

Thanks, Anthony

Answer 1

print('B({})-B({})'.format(ypos, ypos2))

or

print('B(' + str(ypos) + ')-B(' + str(ypos2) + ')')

These should work in Python 2.7 or Python 3.x.

Answer 2

This should be it:

print 'B({})-B({})'.format(ypos, ypos2)

For python2.7 prints are without parentheses, unlike in python3. Check this to verify link