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#!/usr/bin/env python
#-*-encoding: utf-8 -*-

liste = [1, 2, 3, 5]
print liste
for i in range(max(liste)):
  if i in liste:
    print i,'ist in der Liste'
  else:
    liste.append(i)
    print i,'war nicht in der Liste, wurde aber eingefügt'
print sorted(liste)

Code: Alles auswählen

>>> liste = [1, 2, 3, 5]
>>> for index, item in enumerate(range(1, len(liste) + 1)):
...     if liste[index] <> item:
...         print "Erstes fehlendes Element: %i" % i
...     
Erstes fehlendes Element: 4
>>> 

Code: Alles auswählen

>>> liste = [1, 2, 3, 5]
>>> for index, item in enumerate(range(1, len(liste) + 1)):
...     if liste[index] <> item:
...         print "Erstes fehlendes Element: %i" % item
...         break
...     
Erstes fehlendes Element: 4
>>>

Code: Alles auswählen

from itertools import count, ifilter, izip
from operator import itemgetter

def main():
    liste = [1, 2, 3, 5]
    print ifilter(itemgetter(1),
                  ((a, a - b) for a, b in izip(count(1), liste))).next()[0]

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for i in range(1, max(liste)):
....

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>>> liste = [1, 2, 3, 5, 7]
>>> set1 = frozenset(liste)
>>> set2 = frozenset(xrange(1, max(liste) + 1))
>>> print set2.difference(set1)
frozenset([4, 6])
>>> 

Code: Alles auswählen

from itertools import count


def find_missing(iterable, expected_start=1):
    result = list()
    missing = 0
    for expected, number in izip(count(expected_start), iterable):
        diff = number - expected
        if diff != missing:
            result.extend(xrange(expected + missing, expected + diff))
            missing = diff
    return result


def main():
    liste = [2, 3, 5, 8, 9, 11]
    print find_missing(liste)   # -> [1, 4, 6, 7, 10]

Code: Alles auswählen

def find_missing(iterable, expected_start=1):
    diff = []
    expected = expected_start - 1
    for item in iterable:
        expected += 1
        if item == expected:
            continue
        for diff_item in xrange(expected, item):
            diff.append(diff_item)
            expected += 1
    
    return diff

liste = [2, 5, 10]
print find_missing(liste)   # -> [1, 3, 4, 6, 7, 8, 9]