使用正则表达式搜索直到所需的模式 [英] Using regex to search until desired pattern

问题描述

我正在使用以下正则表达式:

I am using the following regex:

orfre = '^(?:...)*?((ATG)(...){%d,}?(?=(TAG|TAA|TGA)))' % (aa)

我基本上想找到所有以ATG开头的序列，然后是三胞胎(例如TTA，TTC，GTC等)，直到找到框架中的终止密码子为止.但是，正如我写的正则表达式一样，如果aa很大，它实际上不会在终止密码子处停止.取而代之的是，它将继续搜索，直到找到一个满足aa的条件为止.我希望它搜索整个字符串，直到找到终止密码子为止.如果匹配时间不够长(对于给定的aa参数)，则应返回None.

I basically want to find all sequences that start with ATG followed by triplets (e.g. TTA, TTC, GTC, etc.) until it finds a stop codon in frame. However, as my regex is written, it won't actually stop at a stop codon if aa is large. Instead, it will keep searching until it finds one such that the condition of aa is met. I would rather have it search the entire string until a stop codon is found. If a match isn't long enough (for a given aa argument) then it should return None.

字符串数据: AAAATGATGCATTAACCCTAATAA

String data: AAAATGATGCATTAACCCTAATAA

正则表达式所需的输出: ATGATGCATTAA

Desired output from regex: ATGATGCATTAA

除非aa> 5，否则不返回任何内容.

Unless aa > 5, in which case nothing should be returned.

我得到的实际输出是:ATGATGCATTAACCCTAA

Actual output I'm getting: ATGATGCATTAACCCTAA

推荐答案

补充说明:如果要检查一个序列中的六个帧，请不要忘记也检查补充链:

Supplementary note: if you want to check the six frames available in one sequence, don't forget to check also the complementary chain:

comp_chain = chain[::-1]    

(-> 扩展切片)

将后面的A音译为T，将G音译为C.

Transliterating latter A's for T's and G's for C's.

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