Printing a polynomial in python

Question

I\'m making a Polynomial python class and as part of that, I need to print a polynomial nicely. The class is given a list that represents the coefficients of the polynomial

Answer 1

Python has really powerful iteration that will help you out here.

For starters, don't pass the len of something to range. Iterate over the something directly.

for x in self.coeffs:

This won't completely help you, though, since the index of the iteration is needed for the power. enumerate can be used for that.

for i, x in enumerate(self.coeffs):

This presents another problem, however. The powers are backwards. For this, you want reversed.

for i, x in enumerate(reversed(self.coeffs)):

From here you just need to handle your output:

items = []
for i, x in enumerate(reversed(self.coeffs)):
    if not x:
        continue
    items.append('{}x^{}'.format(x if x != 1 else '', i))
result = ' + '.join(items)
result = result.replace('x^0', '')
result = result.replace('^1 ', ' ')
result = result.replace('+ -', '- ')