Get words between specific words in a Python string - python

I'm working on getting the words between certain words in a string.
Find string between two substrings Referring to this article, I succeeded in catching words in the following way.
s = 'asdf=5;iwantthis123jasd'
result = re.search('asdf=5;(.*)123jasd', s)
print(result.group(1))
But in the sentence below it failed.
s = ''' <div class="prod-origin-price ">
<span class="discount-rate">
4%
</span>
<span class="origin-price">'''
result = re.search('<span class="discount-rate">(.*)</span>', s)
print(result.group(1))
I'm trying to bring '4%'. Everything else succeeds, but I don't know why only this one fails.
Help

Try this (mind the white spaces and new lines)
import re
s = ''' <div class="prod-origin-price ">
<span class="discount-rate">
4%
</span>
<span class="origin-price">'''
result = re.search('<span class="discount-rate">\s*(.*)\s*</span>', s)
print(result.group(1))

Use re.DOTALL flag for matching new lines:
result = re.search('<span class="discount-rate">(.*)</span>', s, re.DOTALL)
Documentation: https://docs.python.org/3/library/re.html

This is structured data, not just a string, so we can use a library like Beautiful Soup to help us simplify such tasks:
from bs4 import BeautifulSoup
s = ''' <div class="prod-origin-price ">
<span class="discount-rate">
4%
</span>
<span class="origin-price">'''
soup = BeautifulSoup(s)
value = soup.find(class_='discount-rate').get_text(strip=True)
print(value)
# Output:
4%

Related

Dynamically matching a string that starts with a substring

I need to dynamically match a string that starts with forsale_. Here, I'm finding it by hardcoding the characters that follow, but I'd like to do this dynamically:
for_sale = response.html.find('span.forsale_QoVFl > a', first=True)
I tried using startswith(), but I'm not sure how to implement it.
Sample response.html:
<section id="release-marketplace" class="section_9nUx6 open_BZ6Zt">
<header class="header_W2hzl">
<div class="header_3eShg">
<h3>Marketplace</h3>
<span class="forsale_QoVFl">2 For Sale from <span class="price_2Wkos">$355.92</span></span>
</div>
</header>
<div class="content_1TFzi">
<div class="buttons_1G_mP">Buy CDSell CD</div>
</div>
</section>
startswith() is straightforward. x = txt.startswith("forsale_") will return a bool, where txt is the string you want to test.
For more involved pattern matching, you want to look at regular expressions. Something like this is the equivalent of the startswith() line above:
import re
txt = "forsale_arbitrarychars"
x = re.search("^forsale_", txt)
where if you were to replace ^forsale_ with something like ^forsale_[0-9]*$, it would only accept ints after the underscore
I assume your final expected output is the link in the target <span>. If so, I would do it using lxml and xpath:
import lxml.html as lh
sale = """[your html above]"""
doc = lh.fromstring(sale)
print(doc.xpath('//span[#class[starts-with(.,"forsale_")]]/a/#href')[0])
Output:
/sell/release/XXX

Finding id with specific condition in BeautifulSoup

I'm scraping a website with BeautifulSoup in Python
I'd like to find all the a href with id starts with "des "(with space at the tail) + '3-4 letters'
I just tried:
bsObj.findAll("a",{"id":"des "})
But it does not find what I originally intended to.
Do I need to use regex or something?
I would appreciate all your helps. Thanks.
<div>
<a id="des 6TN" href="/en-kr/shop/men/11-by-boris-bidjan-saberi?lvrid=_gm_d6tn">
11 BY BORIS BIDJAN SABERI
</a>
<br/>
<a id="des R6L" href="/en-kr/shop/men/11-eleven?lvrid=_gm_dr6l">
11 ELEVEN
</a>
<br/>
</div>
If you go the regex route, you can pass a compiled regex pattern to the id parameter like so (added an irrelevant/unmatch a tag for demonstration purpose):
from bs4 import BeautifulSoup
import re
​
soup = BeautifulSoup("""<div><a id="des 6TN" href="/en-kr/shop/men/11-by-boris-bidjan-saberi?
lvrid=_gm_d6tn">11 BY BORIS BIDJAN SABERI</a><br /><a id="des R6L" href="/en-
kr/shop/men/11-eleven?lvrid=_gm_dr6l">11 ELEVEN</a><a id="ds R6L" href="/en-
kr/shop/men/11-eleven?lvrid=_gm_dr6l">11 ELEVEN</a><br />""")
soup.find_all('a', id=re.compile('^des \w{3,4}$'))
#[<a href="/en-kr/shop/men/11-by-boris-bidjan-saberi?
# lvrid=_gm_d6tn" id="des 6TN">11 BY BORIS BIDJAN SABERI</a>, <a href="/en-
# kr/shop/men/11-eleven?lvrid=_gm_dr6l" id="des R6L">11 ELEVEN</a>]
Here's another way (not using regex) I don't like regular expressions where I don't need them necessary.
all_des = soup.findAll('a')
#list of every <a> tag
for i in all_des: #loops through all
if i.has_attr('id') and i['id'].startswith('des'):
# check if there is an id within the <a> and if the id starts with des.
print(i)
Output:
<a href="/en-kr/shop/men/11-by-boris-bidjan-saberi?lvrid=_gm_d6tn" id="des 6TN">
11 BY BORIS BIDJAN SABERI
</a>
<a href="/en-kr/shop/men/11-eleven?lvrid=_gm_dr6l" id="des R6L">
11 ELEVEN
</a>
Hopefully, that answers your question, the method above by the awesome '#Psidom' is maybe more convenient to you but I'm pretty confident that pythons inbuilt methods are faster than using regular expressions. Where the regex '^des \w{3,4}$':
**^** asserts position at start of the string
des matches the characters des literally (case sensitive)
**\w{3,4}** matches any word character (equal to [a-zA-Z0-9_])
**{3,4}** Quantifier — Matches between 3 and 4 times, as many times as possible, giving back as needed (greedy)
**$** asserts position at the end of the string

BeautifulSoup search attributes-value

I'm trying to search in HTML documents for specific attribute values.
e.g.
<html>
<h2 itemprop="prio1"> TEXT PRIO 1 </h2>
<span id="prio2"> TEXT PRIO 2 </span>
</html>
I want to find all items with atrributes values beginning with "prio"
I know that I can do something like:
soup.find_all(itemprop=re.compile('prio.*')) )
Or
soup.find_all(id=re.compile('prio.*')) )
But what I am looking for is something like:
soup.find_all(*=re.compile('prio.*')) )
First off your regex is wrong, if you wanted to only find strings starting with prio you would prefix with ^, as it is your regex would match prio anywhere in the string, if you were going to search each attribute you should just use str.startswith:
h = """<html>
<h2 itemprop="prio1"> TEXT PRIO 1 </h2>
<span id="prio2"> TEXT PRIO 2 </span>
</html>"""
soup = BeautifulSoup(h, "lxml")
tags = soup.find_all(lambda t: any(a.startswith("prio") for a in t.attrs.values()))
If you just want to check for certain attributes:
tags = soup.find_all(lambda t: t.get("id","").startswith("prio") or t.get("itemprop","").startswith("prio"))
But if you wanted a more efficient solution you might want to look at lxml which allows you to use wildcards:
from lxml import html
xml = html.fromstring(h)
tags = xml.xpath("//*[starts-with(#*,'prio')]")
print(tags)
Or just id an itemprop:
tags = xml.xpath("//*[starts-with(#id,'prio') or starts-with(#itemprop, 'prio')]")
I don't know if this is the best way, but this works:
>>> soup.find_all(lambda element: any(re.search('prio.*', attr) for attr in element.attrs.values()))
[<h2 itemprop="prio1"> TEXT PRIO 1 </h2>, <span id="prio2"> TEXT PRIO 2 </span>]
In this case, you can access the element use lambda in lambda element:. And we search for 'prio.*' use re.search in the element.attrs.values() list.
Then, we use any() on the result to see if there's an element which has an attribute and it's value starts with 'prio'.
You can also use str.startswith here instead of RegEx since you're just trying to check that attributes-value starts with 'prio' or not, like below:
soup.find_all(lambda element: any(attr.startswith('prio') for attr in element.attrs.values())))

Can I do a findall regular expression like this?

So I need to grab the numbers after lines looking like this
<div class="gridbarvalue color_blue">79</div>
and
<div class="gridbarvalue color_red">79</div>
Is there a way I can do a findAll('div', text=re.recompile('<>)) where I would find tags with gridbarvalue color_<red or blue>?
I'm using beautifulsoup.
Also sorry if I'm not making my question clear, I'm pretty inexperienced with this.
class is a Python keyword, so BeautifulSoup expects you to put an underscore after it when using it as a keyword parameter
>>> soup.find_all('div', class_=re.compile(r'color_(?:red|blue)'))
[<div class="gridbarvalue color_blue">79</div>, <div class="gridbarvalue color_red">79</div>]
To also match the text, use
>>> soup.find_all('div', class_=re.compile(r'color_(?:red|blue)'), text='79')
[<div class="gridbarvalue color_blue">79</div>, <div class="gridbarvalue color_red">79</div>]
import re
elems = soup.findAll(attrs={'class' : re.compile("color_(blue|red)")})
for each e in elems:
m = re.search(">(\d+)<", str(e))
print "The number is %s" % m.group(1)

Want to get part of string using regular expression

I have a string:
<a class="x3-large" href="_ylt=Ats3LonepB5YtO8vbPyjYAWbvZx4;_ylu=X3oDMTVlanQ4dDV1BGEDMTIwOTI4IG5ld3MgZGFkIHNob290cyBzb24gdARjY29kZQNwemJ1ZmNhaDUEY3BvcwMxBGVkAzEEZwNpZC0yNjcyMDgwBGludGwDdXMEaXRjAzAEbWNvZGUDcHpidWFsbGNhaDUEbXBvcwMxBHBrZ3QDMQRwa2d2AzI1BHBvcwMyBHNlYwN0ZC1mZWEEc2xrA3RpdGxlBHRlc3QDNzAxBHdvZQMxMjc1ODg0Nw--/SIG=12uht5d19/EXP=1348942343/**http%3A//news.yahoo.com/conn-man-kills-masked-teen-learns-son-063653076.html" style="font-family: inherit;">Man kills masked teen, learns it's his son</a>
And I want to get only the last part of it, the actual message:
Man kills masked teen, learns it's his son
So far I made something like this:
pattern = '''<a class="x3-large" (.*)">(.*)</a>'''
But It doesn't do what I want, the first (.*) match all crap inside the link, But the second one the actual message that I want to get
In the spirit of answering the question you should have asked instead ;^), yes, you should use BeautifulSoup [link] or lxml or a real parser to handle HTML. For example:
>>> s = '<a class="x3-large" href="_stuff--/SIG**morestuff" style="font-family: inherit;">Man learns not to give himself headaches using regex to deal with HTML</a>'
>>> from bs4 import BeautifulSoup
>>> soup = BeautifulSoup(s)
>>> soup.get_text()
u'Man learns not to give himself headaches using regex to deal with HTML'
Or if there are multiple texts to be captured:
>>> s = '<a class="test" href="ignore1">First sentence</a><a class="test" href="ignore1">Second sentence</a>'
>>> soup = BeautifulSoup(s)
>>> soup.find_all("a")
[<a class="test" href="ignore1">First sentence</a>, <a class="test" href="ignore1">Second sentence</a>]
>>> [a.get_text() for a in soup.find_all("a")]
[u'First sentence', u'Second sentence']
Or if you only want certain values of class:
>>> s = '<a class="test" href="ignore1">First sentence</a><a class="x3-large" href="ignore1">Second sentence</a>'
>>> soup = BeautifulSoup(s)
>>> soup.find_all("a", {"class": "x3-large"})
[<a class="x3-large" href="ignore1">Second sentence</a>]
Type ([^"]*) instead of first (.*) and ([^<]*) instead of second. Or use non greedy quantifiers like (.*?).

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