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Lista-komprehensioner
Listkomprehensioner är ett mycket kraftfullt verktyg, som skapar en ny lista baserad på en annan lista, i en enda, läsbar rad.
Till exempel, låt oss säga att vi behöver skapa en lista med heltal som specificerar längden på varje ord i en viss mening, men endast om ordet inte är ordet "the".
sentence = "the quick brown fox jumps over the lazy dog"
words = sentence.split()
word_lengths = []
for word in words:
if word != "the":
word_lengths.append(len(word))
print(words)
print(word_lengths)
Med hjälp av en listkomprehension kan vi förenkla denna process till denna notation:
sentence = "the quick brown fox jumps over the lazy dog"
words = sentence.split()
word_lengths = [len(word) for word in words if word != "the"]
print(words)
print(word_lengths)
Övning
Använd en listkomprehension för att skapa en ny lista kallad "newlist" från listan "numbers", som endast innehåller de positiva talen från listan som heltal.
numbers = [34.6, -203.4, 44.9, 68.3, -12.2, 44.6, 12.7]
newlist = []
print(newlist)
numbers = [34.6, -203.4, 44.9, 68.3, -12.2, 44.6, 12.7]
newlist = [int(x) for x in numbers if x > 0]
print(newlist)
test_output_contains("[34, 44, 68, 44, 12]")
success_msg("Very nice!")
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