# Exp:
# 若要生成list [1, 2, 3, 4, 5, 6, 7, 8, 9, 10],可以用list(range(1, 11))
# 若要生成[1x1, 2x2, 3x3, ..., 10x10]咋做

L = []
for x in range(1,11):
    L.append(x * x)
print(L)

print('------')

# 使用列表生成式
L2 = [x * x for x in range(1,11)]
print(L2)

print('------')

# 表达式内也可加上判断语句,以进行筛选

L3 = [x * x for x in range(1, 11) if x % 2 == 0]
print(L3)

print('------')

# 使用两层循环

# 使用两层循环,可生成全排列
L = [m + n for m in 'ABC' for n in 'XYZ']

print(L)

# Exp 实际应用: 列出当前目录下所有文件和目录名

import os


L = [d for d in os.listdir('E:\Programming-Sty\Python\exm_python_adv')]

print(L)

# Exp 同时输出字典key和value

D = {'x':'A', 'y':'B', 'z':'C'}

for k, v in D.items():
    print(k, '=', v)

print('------')

print([k + '=' + v for k, v in D.items()])

print('------')

# 将一个list中所有字符串变成小写
L = ['Hello', 'World']

print([s.lower() for s in L])

# 使用if...else语句

# L = [x if x % 2 == 0 for x in range(1, 11)] # if 若在 for 前面则必须加else
# L = [x for x in range(1, 11) if x % 2 == 0 else 0] # 错误的写法
L = [x if x % 2 == 0 else -x for x in range(1,11)]

print(L)