如何捕捉一组中最长的序列 [英] How to catch the longest sequence of a group

问题描述

任务是找到一组中最长的序列

The task is to find the longest sequence of a group

例如，给定DNA序列： AGATCAGATCTTTTTTCTAATGTCTAGGATATATCAGATCAGATCAGATCAGATCAGATC
，它有7次AGATC。 （AGATC）匹配所有匹配项。
是否可以编写仅捕获最长序列的正则表达式，即给定文本中的 AGATCAGATCAGATCAGATCAGATC ？
如果仅使用正则表达式是不可能的，我如何遍历每个序列（即第一个序列是 AGATCAGATC ，第二个序列是 AGATCAGATCAGATCAGATCAGATC 等）在Python中？

for instance, given DNA sequence: "AGATCAGATCTTTTTTCTAATGTCTAGGATATATCAGATCAGATCAGATCAGATCAGATC" and it has 7 occurrences of AGATC. (AGATC) matches all occurrences. Is it possible to write a regular expression that catches only the longest sequence, i.e. AGATCAGATCAGATCAGATCAGATC in the given text? If this is not possible only with regex, how can I iterate through each sequence (i.e. 1st sequence is AGATCAGATC, 2nd - AGATCAGATCAGATCAGATCAGATC et cetera) in python?

推荐答案

使用：

import re

sequence = "AGATCAGATCTTTTTTCTAATGTCTAGGATATATCAGATCAGATCAGATCAGATCAGATC"
matches = re.findall(r'(?:AGATC)+', sequence)

# To find the longest subsequence
longest = max(matches, key=len)

说明：

非捕获组（?: AGATC）+

• + 量词-一次和无限次匹配，例如


• AGATC 字面上匹配字符AGATC（区分大小写）

• + Quantifier — Matches between one and unlimited times, as many times as possible.
• AGATC matches the characters AGATC literally (case sensitive)

结果：

# print(matches)
['AGATCAGATC', 'AGATCAGATCAGATCAGATCAGATC']

# print(longest)
'AGATCAGATCAGATCAGATCAGATC'

您可以测试正则表达式 此处 。

You can test the regex here.

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