python - 列表解析

n = [i for i in  range(0, 11)]
print(n)   # 打印：[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

n = [i+1 if i%2 == 1 else 0 for i in  range(0, 10)]   # if语句在for前面时，必须有else，不然会报错print(n)   # 打印：[0, 2, 0, 4, 0, 6, 0, 8, 0, 10]

n = [i+1 for i in range(0,10) if i%2 == 1]  # if 在后面时，不能有else,不然会报错print(n)   # 打印：[2, 4, 6, 8, 10]

            普通方法
import
             os

file1 = []
for i in os.listdir(‘/tmp/zhangyang‘):  # os.listdir() 列出某路径下的所有文件及文件夹if i.endswith(‘.log‘):  # 筛选出以.log结尾的        file1.append(i)

print(file1)  # 打印[‘2.log‘, ‘1.log‘]

列表解析方法
file2 = [i for i in os.listdir(‘/tmp/zhangyang‘) if i.endswith(‘.log‘)]
print(file2)  # 打印[‘2.log‘, ‘1.log‘]

普通方法
list1 = [‘a‘, ‘b‘, ‘c‘]
list2 = [1, 2, 3]

my_list = []
for x in list1:
    for y in list2:
        my_list.append((x, y))

print(my_list)   # 打印：[(‘a‘, 1), (‘a‘, 2), (‘a‘, 3), (‘b‘, 1), (‘b‘, 2), (‘b‘, 3), (‘c‘, 1), (‘c‘, 2), (‘c‘, 3)]

列表解析方法
my_list2 = [(x, y) for x in list1 for y in list2]
print(my_list2)  # 打印：[(‘a‘, 1), (‘a‘, 2), (‘a‘, 3), (‘b‘, 1), (‘b‘, 2), (‘b‘, 3), (‘c‘, 1), (‘c‘, 2), (‘c‘, 3)]

list1 = [(‘a‘, 1), (‘a‘, 2), (‘a‘, 3), (‘b‘, 1), (‘b‘, 2), (‘b‘, 3), (‘c‘, 1), (‘c‘, 2), (‘c‘, 3)]

my_list = [y for x in list1 for y in x] # 注意两个for的先后顺序，高维在前print(my_list)  # 打印：[‘a‘, 1, ‘a‘, 2, ‘a‘, 3, ‘b‘, 1, ‘b‘, 2, ‘b‘, 3, ‘c‘, 1, ‘c‘, 2, ‘c‘, 3] 

jj = {k: v for k, v in [(1, 201), (2, 201), (3, 205)]}
print(jj)  # 打印:{1: 201, 2: 201, 3: 205}

            print(‘n‘.join([‘‘.join([‘%s*%s=%-2s ‘%(y,x,x*y)for y in range(1,x+1)])for x in range(1,10)]))