How can I exclude a word by using re?

[could ildg]

In re, the punctuation "^" can exclude a single character, but I want
to exclude a whole word now. for example I have a string "hi, how are
you. hello", I want to extract all the part before the world "hello",
I can't use ".*[^hello]" because "^" only exclude single char "h" or
"e" or "l" or "o". Will somebody tell me how to do it? Thanks.

[Christoph Rackwitz]

re.findall('(.* )hello|(.*)', 'hi, how are you. hello')
re.findall('(.* )hello|(.*)', 'hi, how are you. ello')
take a look at the outputs of these.

[Jeff Schwab]

could ildg wrote:

In re, the punctuation "^" can exclude a single character, but I want
to exclude a whole word now. for example I have a string "hi, how are
you. hello", I want to extract all the part before the world "hello",
I can't use ".*[^hello]" because "^" only exclude single char "h" or
"e" or "l" or "o". Will somebody tell me how to do it? Thanks.

import re

def demonstrate(reg ex, text):
pattern = re.compile(rege x)
match = pattern.search( text)

print " ", text
if match:
print " Matched '%s'" % match.group(0)
print " Captured '%s'" % match.group(1)
else:
print " Did not match"

# Option 1: Match it all, but capture only the part before "hello." The
(.*?)
# matches as few characters as possible, so that this pattern would end
before
# the first hello in "hello hello".

pattern = r"(.*?)hello "
print "Option 1:", pattern
demonstrate( pattern, "hi, how are you. hello" )

# Option 2: Don't even match the "hello," but make sure it's there.
# The first of these calls will match, but the second will not. The
# (?=...) construct is using a feature called "forward look-ahead."

pattern = r"(.*)(?=hello) "
print "\nOption 2:", pattern
demonstrate( pattern, "hi, how are you. hello" )
demonstrate( pattern, "hi, how are you. ", )

[could ildg]

Thank you.
But what should I do if there are more than one hello and I only want
to extract what's before the first "hello". For example, the raw
string is "hi, how are you? hello I'm fine, thank you hello. that's it
hello", I want to extract all the stuff before the first hello?

On 14 Aug 2005 08:02:16 -0700, Christoph Rackwitz
<ch************ ****@gmail.com> wrote:

re.findall('(.* )hello|(.*)', 'hi, how are you. hello')
re.findall('(.* )hello|(.*)', 'hi, how are you. ello')
take a look at the outputs of these.

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[Bruno Desthuilliers]

could ildg a écrit :

Thank you.
But what should I do if there are more than one hello and I only want
to extract what's before the first "hello".
Read The Fine Manual ?-)

For example, the raw
string is "hi, how are you? hello I'm fine, thank you hello. that's it
hello", I want to extract all the stuff before the first hello?

re.findall(r'^( .*)hello', your_string_ful l_of_hellos)

[Peter Otten]

could ildg wrote:

But what should I do if there are more than one hello and I only want
to extract what's before the first "hello". For example, the raw
string is "hi, how are you? hello I'm fine, thank you hello. that's it
hello", I want to extract all the stuff before the first hello?

The simplest solution is to use str.split():

helo = "hi, how are you? HELLO I'm fine, thank you hello. that's it"
helo.split("hel lo", 1)[0] "hi, how are you? HELLO I'm fine, thank you "

But regular expressions offer a similar feature:
re.compile("hel lo", re.IGNORECASE). split(helo, 1)[0]

'hi, how are you? '

Peter

[John Machin]

Bruno Desthuilliers wrote:

could ildg a écrit :

Thank you.
But what should I do if there are more than one hello and I only want
to extract what's before the first "hello".

Read The Fine Manual ?-)

For example, the raw
string is "hi, how are you? hello I'm fine, thank you hello. that's it
hello", I want to extract all the stuff before the first hello?

re.findall(r'^( .*)hello', your_string_ful l_of_hellos)

Nice try, but it needs a little refinement to do what the OP asked for:

import re
h = "hi g'day hello hello hello"
re.findall(r'^( .*)hello', h) ["hi g'day hello hello "] re.findall(r'^( .*?)hello', h) ["hi g'day "] re.findall(r'^( .*?)hello', h)[0]

"hi g'day "

[John Machin]

could ildg wrote:

In re, the punctuation "^" can exclude a single character, but I want
to exclude a whole word now. for example I have a string "hi, how are
you. hello", I want to extract all the part before the world "hello",
I can't use ".*[^hello]" because "^" only exclude single char "h" or
"e" or "l" or "o". Will somebody tell me how to do it? Thanks.

(1) Why must you use re? It's often a good idea to use string methods
where they can do the job you want.
(2) What do you want to have happen if "hello" is not in the string?

Example:

C:\junk>type upto.py
def upto(strg, what):
k = strg.find(what)
if k > -1:
return strg[:k]
return None # or raise an exception

helo = "hi, how are you? HELLO I'm fine, thank you hello hello hello.
that's it"

print repr(upto(helo, "HELLO"))
print repr(upto(helo, "hello"))
print repr(upto(helo, "hi"))
print repr(upto(helo, "goodbye"))
print repr(upto("", "goodbye"))
print repr(upto("", ""))

C:\junk>upto.py
'hi, how are you? '
"hi, how are you? HELLO I'm fine, thank you "
''
None
None
''

HTH,
John

[could ildg]

I want to use re because I want to extract something from a html. It
will be very complicated without using re. But while using re, I
found that I must exlude a hole word "</td>", certainly, there are
many many "</td>" in this html.

My re is as below:
_______________ _______________ _______________
r=re.compile(ur 'valign=top>(?P <number>\d{1,2} )</td><td[^>]*>\s{0,2}'
ur'<a href="(?P<url>[^<>]+\.mp3)"( )target=_blank> '
ur'(?P<name>.+) </td>',re.UNICODE |re.IGNORECASE)
_______________ _______________ _______________
There should be over 30 matches in the html. But I find nothing by
re.finditer(htm l) because my last line of re is wrong. I can't use
"(?P<name>. +)</td>" because there are many many "</td>" in the html
and I just want the ".*" to match what are before the firest "</td>".
So I think if there is some idea I can exclude a word, this will be
done. Assume there is "NOT(WORD)" can do it, I just need to write the
last line of the re as "(?P<name>(NOT( </td>))+)</td>".
But I still have no idea after thinking and trying for a very long time.

In other words, I want the "</td>" of "(?P<name>. +)</td>" to be
exactly the first "</td>" in this match. And there is more than one
match in this html, so this must be done by using re.

And I can't use any of your idea because what I want I deal with is a
very complicated html, not just a single line of word.

I can copy part of the html up to here but it's kinda too lengthy.
On 8/15/05, John Machin <sj******@lexic on.net> wrote:

could ildg wrote:

In re, the punctuation "^" can exclude a single character, but I want
to exclude a whole word now. for example I have a string "hi, how are
you. hello", I want to extract all the part before the world "hello",
I can't use ".*[^hello]" because "^" only exclude single char "h" or
"e" or "l" or "o". Will somebody tell me how to do it? Thanks.

(1) Why must you use re? It's often a good idea to use string methods
where they can do the job you want.
(2) What do you want to have happen if "hello" is not in the string?

Example:

C:\junk>type upto.py
def upto(strg, what):
k = strg.find(what)
if k > -1:
return strg[:k]
return None # or raise an exception

helo = "hi, how are you? HELLO I'm fine, thank you hello hello hello.
that's it"

print repr(upto(helo, "HELLO"))
print repr(upto(helo, "hello"))
print repr(upto(helo, "hi"))
print repr(upto(helo, "goodbye"))
print repr(upto("", "goodbye"))
print repr(upto("", ""))

C:\junk>upto.py
'hi, how are you? '
"hi, how are you? HELLO I'm fine, thank you "
''
None
None
''

HTH,
John
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[Jordan Rastrick]

could ildg said:

I want to use re because I want to extract something from a html. It
will be very complicated without using re. But while using re, I
found that I must exlude a hole word "</td>", certainly, there are
many many "</td>" in this html.
Actually, for properly processing html, you shouldn't really be using
regular expressions, precisely because the problem is complicated -
regular expressions are too simple and can't properly model a language
like HTML, which is generated by a context free grammar.

If thats only meaningless technical mumbo-jumbo to you, never mind -
the important point is you shouldn't really use an re. Trust me :)

What you want for a job like is an HTML parser. Theres one in the
standard library; if it doesnt suit, there are plenty of third party
ones. I like Beautiful Soup:

http://www.crummy.com/software/BeautifulSoup/

If you insist on using an re, well I'm sure someone on this group will
figure out a solution to your issue thats as good as you're going to
get...


My re is as below:
_______________ _______________ _______________
r=re.compile(ur 'valign=top>(?P <number>\d{1,2} )</td><td[^>]*>\s{0,2}'
ur'<a href="(?P<url>[^<>]+\.mp3)"( )target=_blank> '
ur'(?P<name>.+) </td>',re.UNICODE |re.IGNORECASE)
_______________ _______________ _______________
There should be over 30 matches in the html. But I find nothing by
re.finditer(htm l) because my last line of re is wrong. I can't use
"(?P<name>. +)</td>" because there are many many "</td>" in the html
and I just want the ".*" to match what are before the firest "</td>".
So I think if there is some idea I can exclude a word, this will be
done. Assume there is "NOT(WORD)" can do it, I just need to write the
last line of the re as "(?P<name>(NOT( </td>))+)</td>".
But I still have no idea after thinking and trying for a very long time.

In other words, I want the "</td>" of "(?P<name>. +)</td>" to be
exactly the first "</td>" in this match. And there is more than one
match in this html, so this must be done by using re.

And I can't use any of your idea because what I want I deal with is a
very complicated html, not just a single line of word.

I can copy part of the html up to here but it's kinda too lengthy.
On 8/15/05, John Machin <sj******@lexic on.net> wrote:

could ildg wrote:

In re, the punctuation "^" can exclude a single character, but I want
to exclude a whole word now. for example I have a string "hi, how are
you. hello", I want to extract all the part before the world "hello",
I can't use ".*[^hello]" because "^" only exclude single char "h" or
"e" or "l" or "o". Will somebody tell me how to do it? Thanks.

(1) Why must you use re? It's often a good idea to use string methods
where they can do the job you want.
(2) What do you want to have happen if "hello" is not in the string?

Example:

C:\junk>type upto.py
def upto(strg, what):
k = strg.find(what)
if k > -1:
return strg[:k]
return None # or raise an exception

helo = "hi, how are you? HELLO I'm fine, thank you hello hello hello.
that's it"

print repr(upto(helo, "HELLO"))
print repr(upto(helo, "hello"))
print repr(upto(helo, "hi"))
print repr(upto(helo, "goodbye"))
print repr(upto("", "goodbye"))
print repr(upto("", ""))

C:\junk>upto.py
'hi, how are you? '
"hi, how are you? HELLO I'm fine, thank you "
''
None
None
''

HTH,
John
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