Python itertools Funktion: inkonsistente Ausgabe

Question

Ich habe darüber nachgedacht, warum die Ausgabe dieser Skripte inkonsistent ist. Könnte mir jemand dabei helfen?

import itertools 
from itertools import tee 
from itertools import islice 

words = ['Salad','with','Chocolate','and','potatoes'] 
nwise = lambda xs,n=2: zip(*(islice(xs,idx,None) for idx,xs in enumerate(tee(xs,n)))) 
doubles = list(map(lambda x: " ".join(x), nwise(words,2))) 
triples = list(map(lambda x: " ".join(x), nwise(words,3))) 
quadrouples = list(map(lambda x: " ".join(x), nwise(words,4))) 
words.extend(doubles) 
words.extend(triples) 
words.extend(quadrouples) 
print(words) 

Das Ergebnis hiervon ist ['Salad', 'with', 'Chocolate', 'and', 'potatoes', 'Salad with', 'with Chocolate', 'Chocolate and', 'and potatoes', 'Salad with Chocolate', 'with Chocolate and', 'Chocolate and potatoes', 'Salad with Chocolate and', 'with Chocolate and potatoes']

import itertools 
from itertools import tee 
from itertools import islice 

words = ['Salad','with','Chocolate','and','potatoes'] 
nwise = lambda xs,n=2: zip(*(islice(xs,idx,None) for idx,xs in enumerate(tee(xs,n)))) 
for i in range(2,5): 
    new = list(map(lambda x: " ".join(x), nwise(words,i))) 
    words.extend(new) 
print(words) 

Das Ergebnis hiervon ist ['Salad', 'with', 'Chocolate', 'and', 'potatoes', 'Salad with', 'with Chocolate', 'Chocolate and', 'and potatoes', 'Salad with Chocolate', 'with Chocolate and', 'Chocolate and potatoes', 'and potatoes Salad with', 'potatoes Salad with with Chocolate', 'Salad with with Chocolate Chocolate and', 'with Chocolate Chocolate and and potatoes', 'Salad with Chocolate and', 'with Chocolate and potatoes', 'Chocolate and potatoes Salad with', 'and potatoes Salad with with Chocolate', 'potatoes Salad with with Chocolate Chocolate and', 'Salad with with Chocolate Chocolate and and potatoes', 'with Chocolate Chocolate and and potatoes Salad with Chocolate', 'Chocolate and and potatoes Salad with Chocolate with Chocolate and', 'and potatoes Salad with Chocolate with Chocolate and Chocolate and potatoes', 'Salad with Chocolate with Chocolate and Chocolate and potatoes and potatoes Salad with', 'with Chocolate and Chocolate and potatoes and potatoes Salad with potatoes Salad with with Chocolate', 'Chocolate and potatoes and potatoes Salad with potatoes Salad with with Chocolate Salad with with Chocolate Chocolate and', 'and potatoes Salad with potatoes Salad with with Chocolate Salad with with Chocolate Chocolate and with Chocolate Chocolate and and potatoes']

Warum bei dem Bereich() -Funktion ist die for-Schleife inkonsistente Ergebnisse der produzieren Linie-für- Linienansatz?

Answer 1

Es ist in der Regel sicherer, create a new collection beim Schleifen zu ändern.

Erweitern Sie eine neue Liste, z. words_:

... 
words_ = [] 
for i in range(2, 5): 
    new = list(map(lambda x: " ".join(x), nwise(words,i))) 
    words_.extend(new) 
print(words_) 

---

Alternativ erstrecken sich die vorhandene words Liste mit einer Liste der new gewünschten Ergebnisse.

ersetzen:

... 
for i in range(2,5): 
    new = list(map(lambda x: " ".join(x), nwise(words,i))) 
    words.extend(new) 
... 

mit

... 
new = [" ".join(x) for i in range(2, 5) for x in nwise(words,i)] 
words.extend(new) 
...