Question

我有以下两个清单：

advanced_filtered_list_val1 = [row for row in cleaned_list if float(row[val1]) < wert1]

advanced_filtered_list_val2 = [row for row in cleaned_list if float(row[val2]) < wert2]

如何使用选项和/或或？

在列表中映射已过滤的列表

列表中的数据是字典，我搜索并过滤此列表中的某些行。我想过滤两个值。这很好用。但是，我现在如何将其映射到列表中进行过滤？

我尝试了以下事项：

select = int(input())

#and operation
if select == 1:
    mapped_list = [row for row in advanced_filtered_list_val1 and advanced_filtered_list_val2]
    for x in mapped_list:
        print(x)
#or operation
if select == 2:
    mapped_list = [row for row in advanced_filtered_list_val1 or advanced_filtered_list_val2]
    for x in mapped_list:
        print(x)

我按如下方式导入数据：

faelle = [{k: v for k, v in row.items()}


for row in csv.DictReader(csvfile, delimiter=";")]

我想立即从wert1和wert2以及wert1或wert2进行过滤。这意味着它应该在and个句子的true子句上，or子句应该是wert1或wert2 True之一}

Answer 1

您希望过滤cleaned_list中包含的词典，这些词典既可以考虑两个wert类似条件（AND），也可以至少考虑其中一个（OR）。你能做的是

import operator as op
ineq_1    = 'gt'
ineq_2    = 'lt'
select    = 2
andor = {
    1:lambda L: filter(
        lambda d: getattr(op,ineq_1)(float(d[val1]), wert1)
                  and getattr(op,ineq_2)(float(d[val2]), wert2),
        L
    ),
    2:lambda L: filter(
        lambda d: getattr(op,ineq_1)(float(d[val1]), wert1)
                  or getattr(op,ineq_2)(float(d[val2]), wert2),
        L
    ),
}

mapped_list = andor[select](cleaned_list)
for x in mapped_list:
    print(dict(x))

可能的选择是gt（大于），lt（低于）或eq。

<小时/> 请注意，您甚至可以使事情变得更加活跃＆＃34;动态＆＃34;同样使用python-builtin模块operator的方法and_和or_。例如，执行

#Where the two following ix2-like stuffs are defined to make
# a correspondence between names one knows, and methods of the
#  module operator.
ix2conj = {
    1:'and_',
    2:'or_',
}
ix2ineq = {
    '<' :'lt',
    '==':'eq',
    '>' :'gt',
}
def my_filter(conjunction, inequality1, inequality2, my_cleaned_list):
    return filter(
        lambda d: getattr(op, ix2conj[conjunction])(
                       getattr(op, ix2ineq[inequality1])(float(d[val1]), wert1),
                       getattr(op, ix2ineq[inequality2])(float(d[val2]), wert2)
                       ),
        my_cleaned_list
        )

ineq_1    = '>'
ineq_2    = '<'
select    = 2
print(my_filter(select, ineq_1, ineq_2, cleaned_list))

Answer 2

我看到你的语法来自哪里，但这不是python中的“和”和“或”关键字所做的。为了做你想要的，我想你会想要使用内置类型set。你可以做点什么

# note that this is already the "or" one
both = list1 + [x for x in list2 if not x in list1]

# for "and"
mapped_list = [x for x in both if x in list1 and x in list2]

如果您希望结果列表只包含唯一值;否则你可以用

做同样的事情

both = list1 + list2

如何使用运算符'和'和/或'或'

2 个答案: