Python 2.4.3
我需要阅读一些文件（可以大到10GB）。我需要它做的是浏览文件，直到它匹配模式。然后打印该行以及后面的每一行，直到它与另一个模式匹配。此时，继续读取文件直到下一个模式匹配。
例如。文件包含。
---- Alpha ---- Zeta
...(text lines)
---- Bravo ---- Delta
...(text lines)
等
如果匹配---- Alpha ---- Zeta，它应该打印---- Alpha ---- Zeta和之后的每一行直到它遇到---- Bravo ---- Delta（或除了----阿尔法----泽塔（Zeta）之外，它会直接读到它直到匹配----阿尔法----泽塔再次。
以下内容与我正在寻找的内容相匹配 - 但仅打印匹配的行 - 而不是其后的文本。
知道我哪里出错吗？
import re
fh = open('text.txt', 'r')
re1='(-)' # Any Single Character 1
re2='(-)' # Any Single Character 2
re3='(-)' # Any Single Character 3
re4='(-)' # Any Single Character 4
re5='( )' # White Space 1
re6='(Alpha)' # Word 1
re6a='((?:[a-z][a-z]+))' # Word 1 alternate
re7='( )' # White Space 2
re8='(-)' # Any Single Character 5
re9='(-)' # Any Single Character 6
re10='(-)' # Any Single Character 7
re11='(-)' # Any Single Character 8
re12='(\\s+)' # White Space 3
re13='(Zeta)' # Word 2
re13a='((?:[a-z][a-z]+))' # Word 2 alternate
rg = re.compile(re1+re2+re3+re4+re5+re6+re7+re8+re9+re10+re11+re12+re13,re.IGNORECASE|re.DOTALL)
rga = re.compile(re1+re2+re3+re4+re5+re6a+re7+re8+re9+re10+re11+re12+re13a,re.IGNORECASE|re.DOTALL)
for line in fh:
if re.match(rg, line):
print line
fh.next()
while not re.match(rga, line):
print fh.next()
fh.close()
和我的示例文本文件。
---- Pappa ---- Oscar
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Mauris eleifend imperdiet
lacus quis imperdiet. Nulla erat neque, laoreet vel fermentum a, dapibus in sem.
Maecenas elementum nisi nec neque pellentesque ac rutrum urna cursus. Nam non purus
sit amet dolor fringilla venenatis. Integer augue neque, scelerisque ac dictum at,
venenatis elementum libero. Etiam nec ante in augue porttitor laoreet. Aenean ultrices
pellentesque erat, id porta nulla vehicula id. Cras eu ante nec diam dapibus hendrerit
in ac diam. Vivamus velit erat, tincidunt id tempus vitae, tempor vel leo. Donec
aliquam nibh mi, non dignissim justo.
---- Alpha ---- Zeta
Sed molestie tincidunt euismod. Morbi ultrices diam a nibh varius congue. Nulla velit
erat, luctus ac ornare vitae, pharetra quis felis. Sed diam orci, accumsan eget
commodo eu, posuere sed mi. Phasellus non leo erat. Mauris turpis ipsum, mollis sed
ismod nec, aliquam non quam. Vestibulum sem eros, euismod ut pharetra sit amet,
dignissim eget leo.
---- Charley ---- Oscar
Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.
Aliquam commodo, metus at vulputate hendrerit, dui justo tempor dui, at posuere
ante vitae lorem. Fusce rutrum nibh a erat condimentum laoreet. Nullam eu hendrerit
sapien. Suspendisse id lobortis urna. Maecenas ut suscipit nisi. Proin et metus at
urna euismod sollicitudin eu at mi. Aliquam ac egestas magna. Quisque ac vestibulum
lectus. Duis ac libero magna, et volutpat odio. Cras mollis tincidunt nibh vel rutrum.
Curabitur fringilla, ante eget scelerisque rhoncus, libero nisl porta leo, ac
vulputate mi erat vitae felis. Praesent auctor fringilla rutrum. Aenean sapien ligula,
imperdiet sodales ullamcorper ut, vulputate at enim.
---- Bravo ---- Delta
Donec cursus tincidunt pellentesque. Maecenas neque nisi, dignissim ac aliquet ac,
vestibulum ut tortor. Pellentesque habitant morbi tristique senectus et netus et
malesuada fames ac turpis egestas. Aenean ullamcorper dapibus accumsan. Aenean eros
tortor, ultrices at adipiscing sed, lobortis nec dolor. Fusce eros ligula, posuere
quis porta nec, rhoncus et leo. Curabitur turpis nunc, accumsan posuere pulvinar eget,
sollicitudin eget ipsum. Sed a nibh ac est porta sollicitudin. Pellentesque ut urna ut
risus pharetra mollis tincidunt sit amet sapien. Sed semper sollicitudin eros quis
pellentesque. Curabitur ac metus lorem, ac malesuada ipsum. Nulla turpis erat, congue
eu gravida nec, egestas id nisi. Praesent tellus ligula, pretium vitae ullamcorper
vitae, gravida eu ipsum. Cras sed erat ligula.
---- Alpha ---- Zeta
Cras id condimentum lectus. Sed sit amet odio eros, ut mollis sapien. Etiam varius
tincidunt quam nec mattis. Nunc eu varius magna. Maecenas id ante nisl. Cras sed augue
ipsum, non mollis velit. Fusce eu urna id justo sagittis laoreet non id urna. Nullam
venenatis tincidunt gravida. Proin mattis est sit amet dolor malesuada sagittis.
Curabitur in lacus rhoncus mi posuere ullamcorper. Phasellus eget odio libero, ut
lacinia orci. Pellentesque iaculis, ligula at varius vulputate, arcu leo dignissim
massa, non adipiscing lectus magna nec dolor. Quisque in libero nec orci vestibulum
dapibus. Nulla turpis massa, varius quis gravida eu, bibendum et nisl. Fusce tincidunt
laoreet elit, sed egestas diam pharetra eget. Maecenas lacus velit, egestas nec tempor
eget, hendrerit et massa.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++
以下代码确实有效 - 它在标题类型行上匹配 - 打印它后面的每一行，直到下一个标题类型模式 - 这是不匹配的，跳过下一个标题类型模式。
唯一的问题是 - 它真的很慢。通过10米线路需要大约一分钟。
re1='(-)' # Any Single Character 1
re2='(-)' # Any Single Character 2
re3='(-)' # Any Single Character 3
re4='(-)' # Any Single Character 4
re5='( )' # White Space 1
re6='(Alpha)' # Word 1
re6a='((?:[a-z][a-z]+))' # Word 1 alternate
re7='( )' # White Space 2
re8='(-)' # Any Single Character 5
re9='(-)' # Any Single Character 6
re10='(-)' # Any Single Character 7
re11='(-)' # Any Single Character 8
re12='(\\s+)' # White Space 3
re13='(Zeta)' # Word 2
re13a='((?:[a-z][a-z]+))' # Word 2 alternate
rg = re.compile(re1+re2+re3+re4+re5+re6+re7+re8+re9+re10+re11+re12+re13,re.IGNORECASE|re.DOTALL)
rga = re.compile(re1+re2+re3+re4+re5+re6a+re7+re8+re9+re10+re11+re12+re13a,re.IGNORECASE|re.DOTALL)
linestop = 0
fh = open('test.txt', 'r')
for line in fh:
if linestop == 0:
if re.match(rg, line):
print line
linestop = 1
else:
if re.match(rga, line):
linestop = 0
else:
print line
fh.close()
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++即grep out - 然后运行上面的正则表达式脚本。
我让os.system运行良好 - 我无法看到如何通过pOpen传递正则表达式匹配
** * * 最终更新 * ** * ** * ** *
我称之为已完成。我最终做的是：
净结果是从大约65秒读取1000万行文件 - 打印出必要的项目 - 大约3.5秒。我希望我能想出如何传递grep而不是os.system - 但也许它在python 2.4中没有得到很好的支持
答案 0 :(得分：3)
我认为没有必要在这里使用正则表达式。并不是说它们那么糟糕，但如果你正在寻找这样一个特定的模式，那么使用正则表达式就太过分了。尝试这样的事情：
def record(filename, pattern):
with open(filename) as file:
recording = False
for line in file:
if line.startswith(pattern):
yield line
recording = not recording
elif recording:
yield line
使用文件名调用record，您的模式会为您提供一个生成一行的生成器对象。处理大文件时这样做更好，因此您不必立即将它们混淆。
打印您的行可以像这样工作 - 假设您的文件名为example.txt：
for rec in record(filename, '---- Alpha ---- Zeta'):
print rec
准确地说：record生成器生成包含换行符的行，因此您可能希望join将它们重新组合在一起，而不会有任何其他换行符：
print "".join(list(record(filename, '---- Alpha ---- Zeta')))
答案 1 :(得分：2)
你仍然匹配线，因为你仍然在for循环的同一个迭代中，所以不会改变。