通过代码实例展示Python中列表生成式的用法

squares = []
for x in range(10):
 squares.append(x**2)

squares = [x**2 for x in range(10)]

numbers = []
for x in range(100):
 if x % 3 == 0:
  numbers.append(x)

numbers = [x for x in range(100) if x % 3 == 0]

noprimes = []
for i in range(2, 8):
 for j in range(i*2, 50, i):
  noprimes.append(j)
primes = []
for x in range(2, 50):
 if x not in noprimes:
  primes.append(x)

noprimes = [j for i in range(2, 8) for j in range(i*2, 50, i)]
primes = [x for x in range(2, 50) if x not in noprimes]

noprimes = set(j for i in range(2, 8) for j in range(i*2, 50, i))
primes = [x for x in range(2, 50) if x not in noprimes]

matrix = [[0,1,2,3], [4,5,6,7], [8,9,10,11]]

flattened = []
for row in matrix:
 for i in row:
  flattened.append(i)

flattened = [i for row in matrix for i in row]

from random import random
results = []
for x in range(10):
 results.append(int(round(random())))

from random import random
results = [int(round(random())) for x in range(10)]

sentence = 'Your mother was a hamster'

vowels = 'aeiou'
non_list = []
for l in sentence:
 if not l in vowels:
  non_list.append(l)
nonvowels = ''.join(non_list)

vowels = 'aeiou'
nonvowels = ''.join([l for l in sentence if not l in vowels])

vowels = 'aeiou'
nonvowels = ''.join(l for l in sentence if not l in vowels)

import os
files = []
for f in os.listdir('./my_dir'):
 if f.endswith('.txt'):
  files.append(f)

import os
files = [f for f in os.listdir('./my_dir') if f.endswith('.txt')]

import os
files = [os.path.join('./my_dir', f) for f in os.listdir('./my_dir') if f.endswith('.txt')]

import csv
data = []
for x in csv.DictReader(open('file.csv', 'rU')):
 data.append(x)

import csv
data = [ x for x in csv.DictReader(open('file.csv', 'rU'))]