Python筛选列表中指定的值，返回新列表

场景

简单筛选

# 筛选【剑】系武器
ls1 = ['木剑', '落日弓', '蛋刀', '峨眉刺', '双铁戟']
ls2 = filter(lambda x: '剑' in x, ls1)
print(list(ls2))

[‘木剑’]

筛选ls1中，含ls2的元素

# 筛选【剑、刀、枪】系武器
ls1 = ['木剑', '落日弓', '蛋刀', '峨眉刺', '双铁戟']
ls2 = ['剑', '刀', '枪']
ls3 = []
for i in ls1:
    for j in ls2:
        if j in i:
            ls3.append(i)
            break
print(ls3)

[‘木剑’, ‘蛋刀’]

筛选ls1中，不含ls2的元素

# 反选【剑、刀、枪】系武器
ls1 = ['木剑', '落日弓', '蛋刀', '峨眉刺', '双铁戟']
ls2 = ['剑', '刀', '枪']
ls3 = []
for i in ls1:
    for j in ls2:
        if j in i:
            break
    else:
        ls3.append(i)
print(ls3)

[‘落日弓’, ‘峨眉刺’, ‘双铁戟’]

去重（保留顺序）

ls1 = [1, 2, 3, 1, 5, 6, 7, 2]
ls2 = []
for i in ls1:
    if i not in ls2:
        ls2.append(i)
print(ls2)

[1, 2, 3, 5, 6, 7]