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Lister Forståelse
List Comprehensions er et meget kraftfuldt værktøj, der skaber en ny liste baseret på en anden liste i en enkelt, læsbar linje.
For eksempel, lad os sige, at vi skal lave en liste af heltal, der angiver længden af hvert ord i en bestemt sætning, men kun hvis ordet ikke er 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)
Ved hjælp af en list comprehension kunne vi forenkle denne proces til denne 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)
Øvelse
Ved hjælp af en list comprehension, lav en ny liste kaldet "newlist" ud fra listen "numbers", som kun indeholder de positive tal fra listen 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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