如何从字符串中删除不需要的字符，如空格和换行符

debugcn 发表于 Dev

用户2935002

最近，我写了一个python脚本，从数据库中下载序列，如果您提供登录号（例如Rv1617），它将给出如下所示的输出

import wget
import re
from HTMLParser import HTMLParser
e = raw_input("Enter the correct accession number.: ")
y = ''.join([i for i in e if i.isdigit()])
#print y
url = "http://tuberculist.epfl.ch/quicksearch.php?gene+name="+y+"&submit=Search#sequence"
#print url
filname = wget.download(url)
a = open(filname,'r')
b = a.readlines()
f = "|"+e+"|"

for c in b:
    if f in c:
        #x = c
        pattern = re.compile("> >.+<br /></")
        z = pattern.findall(c)
        #print z

class MyHTMLParser(HTMLParser):
    def handle_data(self, data):
        final = ''.join(data)
        andfinal = final.replace(" ","")
        print andfinal,
# instantiate the parser and fed it some HTML

for xz in z:
    parser = MyHTMLParser()
    parser.feed(xz)

它将下载如下序列：

>>>
Enter the correct accession number.:Rv1617

>>M.tuberculosisH37Rv|Rv1617|pykA
VTRRGKIVCTLGPATQRDDLVRALVEAGMDVARMNFSHGDYDDHKVAYERVRVASDATGR
AVGVLADLQGPKIRLGRFASGATHWAEGETVRITVGACEGSHDRVSTTYKRLAQDAVAGD
RVLVDDGKVALVVDAVEGDDVVCTVVEGGPVSDNKGISLPGMNVTAPALSEKDIEDLTFA
LNLGVDMVALSFVRSPADVELVHEVMDRIGRRVPVIAKLEKPEAIDNLEAIVLAFDAVMV
ARGDLGVELPLEEVPLVQKRAIQMARENAKPVIVATQMLDSMIENSRPTRAEASDVANAV
LDGADALMLSGETSVGKYPLAAVRTMSRIICAVEENSTAAPPLTHIPRTKRGVISYAARD
IGERLDAKALVAFTQSGDTVRRLARLHTPLPLLAFTAWPEVRSQLAMTWGTETFIVPKMQ
STDGMIRQVDKSLLELARYKRGDLVVIVAGAPPGTVGSTNLIHVHRIGEDDV

第一行很好，但其余行具有换行符或空格，应在输出中将其删除，并且输出应如下所示：

 >>M.tuberculosisH37Rv|Rv1617|pykA
VTRRGKIVCTLGPATQRDDLVRALVEAGMDVARMNFSHGDYDDHKVAYERVRVASDATGRAVGVLADLQGPKIRLGRFASGATHWAEGETVRITVGACEGSHDRVSTTYKRLAQDAVAGDRVLVDDGKVALVVDAVEGDDVVCTVVEGGPVSDNKGISLPGMNVTAPALSEKDIEDLTFALNLGVDMVALSFVRSPADVELVHEVMDRIGRRVPVIAKLEKPEAIDNLEAIVLAFDAVMV

我已经尝试过：

andfinal = final.replace(" ","")

它适用于空格，但不适用于换行符。

请建议我应该进行哪些更改：

谢谢并恭祝安康

马丁·彼得斯（Martijn Pieters）

在换行符上分割字符串，然后重新加入行：

final_lines = final.splitlines()
final = final_lines[0] + '\n' + ''.join(final_lines[1:])

演示：

>>> final = '''\
... >M. tuberculosis H37Rv|Rv1617|pykA
... VTRRGKIVCTLGPATQRDDLVRALVEAGMDVARMNFSHGDYDDHKVAYERVRVASDATGR
... AVGVLADLQGPKIRLGRFASGATHWAEGETVRITVGACEGSHDRVSTTYKRLAQDAVAGD
... RVLVDDGKVALVVDAVEGDDVVCTVVEGGPVSDNKGISLPGMNVTAPALSEKDIEDLTFA
... LNLGVDMVALSFVRSPADVELVHEVMDRIGRRVPVIAKLEKPEAIDNLEAIVLAFDAVMV
... ARGDLGVELPLEEVPLVQKRAIQMARENAKPVIVATQMLDSMIENSRPTRAEASDVANAV
... LDGADALMLSGETSVGKYPLAAVRTMSRIICAVEENSTAAPPLTHIPRTKRGVISYAARD
... IGERLDAKALVAFTQSGDTVRRLARLHTPLPLLAFTAWPEVRSQLAMTWGTETFIVPKMQ
... STDGMIRQVDKSLLELARYKRGDLVVIVAGAPPGTVGSTNLIHVHRIGEDDV
... '''
>>> final_lines = final.splitlines()
>>> print final_lines[0] + '\n' + ''.join(final_lines[1:])
>M. tuberculosis H37Rv|Rv1617|pykA
VTRRGKIVCTLGPATQRDDLVRALVEAGMDVARMNFSHGDYDDHKVAYERVRVASDATGRAVGVLADLQGPKIRLGRFASGATHWAEGETVRITVGACEGSHDRVSTTYKRLAQDAVAGDRVLVDDGKVALVVDAVEGDDVVCTVVEGGPVSDNKGISLPGMNVTAPALSEKDIEDLTFALNLGVDMVALSFVRSPADVELVHEVMDRIGRRVPVIAKLEKPEAIDNLEAIVLAFDAVMVARGDLGVELPLEEVPLVQKRAIQMARENAKPVIVATQMLDSMIENSRPTRAEASDVANAVLDGADALMLSGETSVGKYPLAAVRTMSRIICAVEENSTAAPPLTHIPRTKRGVISYAARDIGERLDAKALVAFTQSGDTVRRLARLHTPLPLLAFTAWPEVRSQLAMTWGTETFIVPKMQSTDGMIRQVDKSLLELARYKRGDLVVIVAGAPPGTVGSTNLIHVHRIGEDDV

但是，请考虑到FAST格式专门允许换行，并且不错的FASTA格式库可以为您解释字符串。

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