Question

我正在处理一个字符串列表。我想查找给定元素的列表，如果找到，我想返回从切片前的n个索引到找到的元素后的n个索引的列表切片。

str_list = ['str1','str2','str3','str4','str5','str6','str7','str8']
for i in str_list:
    for elem in str_list:
        if '5' in elem:
            print(elem in range(str_list[i-2:i+3]))

#expected output
['str3','str4','str5','str6','str7']

Answer 1

尝试一下：

str_list = ['str1','str2','str3','str4','str5','str6','str7','str8']

for c,i in enumerate(str_list):
    if '5' in i:
        new = str_list[c-2:c+3]

In [1068]: new
Out[1068]: ['str3', 'str4', 'str5', 'str6', 'str7']

Answer 2

您可以enumerate列表并遍历列表，从而在与您的条件相符的每个元素上产生一个切片：

def slices(sequence, radius, condition):
    for i, x in enumerate(sequence):
        if condition(x):
            begin = i - radius
            begin = 0 if begin < 0 else begin
            end = i+radius+1
            yield sequence[begin:end]

print(list(slices(str_list, 2, lambda s: '5' in s)))
# [['str3', 'str4', 'str5', 'str6', 'str7']]

Python 3-列表切片-查找给定元素并返回列表的切片[elem-10：elem + 10]）

2 个答案: