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def grfAbleiten(Summand, var0int): #var0int=Variable of Interest.
    end=len(Summand[2])             #how many variables to check?
    for i in range (0,end,1):       #which variable is asked for?
        if(var0int==Summand[2][i]):
            var0int=i               #change var0int to list number
    Ableitung=Summand
    Ableitung[1]=int(Ableitung[3][var0int])*int(Ableitung[1])#actual derivation
    print(Summand)
    Ableitung[3][var0int]=int(Ableitung[3][var0int])-1    #actual derivation
    print(Summand)
    ##print(Ableitung)
    return(Ableitung)

def expAbleiten(Summand, var0int):
    nachDif=grfAbleiten(Summand[1:],var0int) #Bisher nur für grfAbleitung
    Ableitung=[5,nachDif,Summand]   #Kettenregel der Ableitung
    return Ableitung

Code: Alles auswählen

#!/usr/bin/env python
# coding: utf8
from __future__ import absolute_import, division, print_function
from collections import namedtuple


Exponent = namedtuple('Exponent', 'coefficient variable_name exponent')


def exponent2str(exponent):
    result = list()
    if exponent.coefficient != 1:
        result.append(str(exponent.coefficient))
    if exponent.coefficient != 0 and exponent.exponent != 0:
        if result:
            result.append('*')
        result.append(exponent.variable_name)
        if exponent.exponent != 1:
            result.append('^{0}'.format(exponent.exponent))
    return ''.join(result)


def diff_exponent(exponent, variable_name):
    if exponent.variable_name == variable_name and exponent.exponent != 0:
        return Exponent(
            exponent.coefficient * exponent.exponent,
            exponent.variable_name,
            exponent.exponent - 1
        )
    else:
        return None


def sum2str(exponents):
    return ' + '.join(exponent2str(e) for e in exponents)


def diff_sum(exponents, variable_name):
    result = list()
    for exponent in exponents:
        diff = diff_exponent(exponent, variable_name)
        if diff is not None:
            result.append(diff)
    return result


def main():
    summands = [
        Exponent(1, 'a', 42), Exponent(2, 'b', 23), Exponent(3, 'a', 4711),
        Exponent(4, 'a', 2), Exponent(5, 'a', 1), Exponent(6, 'a', 0),
    ]
    print(sum2str(summands))
    print(sum2str(diff_sum(summands, 'a')))


if __name__ == '__main__':
    main()

Code: Alles auswählen

a^42 + 2*b^23 + 3*a^4711 + 4*a^2 + 5*a + 6
42*a^41 + 14133*a^4710 + 8*a + 5

Code: Alles auswählen

#!/usr/bin/env python
# coding: utf8
from __future__ import absolute_import, division, print_function
import re


class Exponent(object):

    RE = re.compile(
        r'\s*((?P<coeff>-?\d+)\s*\*?\s*)?'
        r'(?P<var>[a-z])?\s*'
        r'(\^(?P<exp>-?\d+))?\s*'
    )

    def __init__(self, coefficient, variable_name, exponent):
        self.coefficient = coefficient
        self.variable_name = variable_name
        self.exponent = exponent
 
    def __str__(self):
        result = list()
        if self.coefficient != 1:
            result.append(str(self.coefficient))
        if self.coefficient != 0 and self.exponent != 0:
            if result:
                result.append('*')
            result.append(self.variable_name)
            if self.exponent != 1:
                result.append('^{0}'.format(self.exponent))
        return ''.join(result)
 
    def diff(self, variable_name):
        if self.variable_name == variable_name and self.exponent != 0:
            return Exponent(
                self.coefficient * self.exponent,
                self.variable_name,
                self.exponent - 1
            )
        else:
            return None

    @classmethod
    def from_string(cls, string):
        match = cls.RE.match(string)
        coefficient = int(match.group('coeff') or 1)
        variable_name = match.group('var') or ''
        exponent = int(match.group('exp') or (1 if variable_name else 0))
        return cls(coefficient, variable_name, exponent)

 
class Sum(object):

    def __init__(self, summands):
        self.summands = summands

    def __iter__(self):
        return iter(self.summands)

    def __str__(self):
        return ' + '.join(str(summand) for summand in self)
 
    def diff(self, variable_name):
        result = list()
        for summand in self:
            diff = summand.diff(variable_name)
            if diff is not None:
                result.append(diff)
        return Sum(result)

    @classmethod
    def from_string(cls, string):
        return cls(map(Exponent.from_string, string.split('+')))


def main():
    summands = Sum.from_string('a^42 + 2*b^23 + 3*a^4711 + 4*a^2 + 5*a + 6')
    assert str(summands) == str(Sum.from_string(str(summands)))
    print(summands)
    print(summands.diff('a'))
 
 
if __name__ == '__main__':
    main()