Using Regexp to catch substring python - python

Let's assume I have some string like that:
x = 'Wish she could have told me herself. #NicoleScherzy #nicolescherzinger #OneLove #myfav #MyQueen :heavy_black_heart::heavy_black_heart: some string too :smiling_face:'
So, I want to get from that :
:heavy_black_heart:
:smiling_face:
To do that I did the following :
import re
result = re.search(':(.*?):', x)
result.group()
It only gives me the ':heavy_black_heart:' . How could I make it work ? If possible I want to store them in dictonary after I found all of them.

print re.findall(':.*?:', x) is doing the job.
Output:
[':heavy_black_heart:', ':heavy_black_heart:', ':smiling_face:']
But if you want to remove the duplicates:
Use:
res = re.findall(':.*?:', x)
dictt = {x for x in res}
print list(dictt)
Output:
[':heavy_black_heart:', ':smiling_face:']

You seem to want to match smilies that are some symbols in-between 2 :s. The .*? can match 0 symbols, and your regex can match ::, which I think is not what you would want to get. Besdies, re.search only returns one - the first - match, and to get multiple matches, you usually use re.findall or re.finditer.
I think you need
set(re.findall(r':[^:]+:', x))
or if you only need to match word chars inside :...::
set(re.findall(r':\w+:', x))
or - if you want to match any non-whitespace chars in between two ::
set(re.findall(r':[^\s:]+:', x))
The re.findall will find all non-overlapping occurrences and set will remove dupes.
The patterns will match :, then 1+ chars other than : ([^:]+) (or 1 or more letters, digits and _) and again :.
>>> import re
>>> x = 'Wish she could have told me herself. #NicoleScherzy #nicolescherzinger #OneLove #myfav #MyQueen :heavy_black_heart::heavy_black_heart: some string too :smiling_face:'
>>> print(set(re.findall(r':[^:]+:', x)))
{':smiling_face:', ':heavy_black_heart:'}
>>>

try this regex:
:([a-z0-9:A-Z_]+):

import re
x = 'Wish she could have told me herself. #NicoleScherzy #nicolescherzinger #OneLove #myfav #MyQueen :heavy_black_heart::heavy_black_heart: some string too :smiling_face:'
print set(re.findall(':.*?:', x))
output:
{':heavy_black_heart:', ':smiling_face:'}

Just for fun, here's a simple solution without regex. It splits around ':' and keeps the elements with odd index:
>>> text = 'Wish she could have told me herself. #NicoleScherzy #nicolescherzinger #OneLove #myfav #MyQueen :heavy_black_heart::heavy_black_heart: some string too :smiling_face:'
>>> text.split(':')[1::2]
['heavy_black_heart', 'heavy_black_heart', 'smiling_face']
>>> set(text.split(':')[1::2])
set(['heavy_black_heart', 'smiling_face'])

Related

Insert Colon between each element of a list python

[x[1] for x in matches]
x
newtest = [x2[-2:] for x2 in x]
newtest
I have a list
[u'asvbsMasd', u'abdhesMrty', u'ahdksC', u'ahdeO', u'ahdnL', u'ahddsS',]
now i want my list to be like a colon between where it finds a lower case and upper case
[u'asvbs:Masd', u'abdhes:Mrty', u'ahdks:C', u'ahde:Oqqq', u'ahdn:L', u'ahdds:S',]
You need to write a regex that matches <lowercase><uppercase> pair:
>>> import re
>>> r = re.compile(r'([a-z])([A-Z])')
Note the letters itself marked as a groups via (). If you have regex matching the pair and the neighbor letters as two separate groups, you may just use the substitution (\1 and \2 are places where matched groups are put into the substitution string):
>>> r.sub(r'\1:\2', u'asvbsMasd')
u'asvbs:Masd'
Then you can use list comprehension to apply that substitution to each element of a list:
>>> l = [u'asvbsMasd', u'abdhesMrty', u'ahdksC', u'ahdeO', u'ahdnL', u'ahddsS']
>>> [r.sub(r'\1:\2', s) for s in l]
[u'asvbs:Masd', u'abdhes:Mrty', u'ahdks:C', u'ahde:O', u'ahdn:L', u'ahdds:S']
Or if you want it wrapped into a function:
import re
re_lowerupper = r = re.compile(r'([a-z])([A-Z])')
def add_colons(l):
global re_lowerupper
return [re_lowerupper.sub(r'\1:\2', s) for s in l]
print add_colons([u'asvbsMasd', u'abdhesMrty', u'ahdksC', u'ahdeO', u'ahdnL', u'ahddsS'])
You may of course simplify it just to a single lambda, like in the next example.
One importand disclaimer, as I see you use Unicode strings: there is no easy way of finding arbitrary Unicode upper/lowercase character. There is no shorthand defined like for matching any digit (\d) or any alphanumeric character (\w). If you need to match diacritics too, you may need to list the lowercase and uppercase diacritics of your language explicitly in the regex, like:
re_lower = ur'[a-zßàáâãäåæçèéêëìíîïðñòóôõöùúûüýþÿāăąćĉčēĕėęěğģĥĩīĭįĵķļľŀłņňŋōŏőœŕŗřśŝşţťũūŭůűųŵŷźžǎǐǒǔǖǘǚǜǩǫǵǹȟȧȩȯȳəḅḋḍḑḟḡḣḥḧḩḱḳṃṕṗṙṛṡṣṫṭṽẁẃẅẇẉẍẏẑẓẗẘẙạẹẽịọụỳỵỹ]'
re_upper = ur'[A-ZÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖÙÚÛÜÝÞĀĂĄĆĈČĒĔĖĘĚĞĢĤĨĪĬĮİĴĶĻĽĿŁŅŇŊŌŎŐŒŔŖŘŚŜŞŢŤŨŪŬŮŰŲŴŶŸŹŽƏǍǏǑǓǕǗǙǛǨǪǴǸȞȦȨȮȲḄḊḌḐḞḠḢḤḦḨḰḲṂṔṖṘṚṠṢṪṬṼẀẂẄẆẈẌẎẐẒẠẸẼỊỌỤỲỴỸ]'
re_lowerupper = re.compile('(%s)(%s)' % (re_lower, re_upper))
add_colons = lambda l: [re_lowerupper.sub(r'\1:\2', s) for s in l]
This should do the job for the Latin script European languages.

How to parse values appear after the same string in python?

I have a input text like this (actual text file contains tons of garbage characters surrounding these 2 string too.)
(random_garbage_char_here)**value=xxx**;(random_garbage_char_here)**value=yyy**;(random_garbage_char_here)
I am trying to parse the text to store something like this:
value1="xxx" and value2="yyy".
I wrote python code as follows:
value1_start = content.find('value')
value1_end = content.find(';', value1_start)
value2_start = content.find('value')
value2_end = content.find(';', value2_start)
print "%s" %(content[value1_start:value1_end])
print "%s" %(content[value2_start:value2_end])
But it always returns:
value=xxx
value=xxx
Could anyone tell me how can I parse the text so that the output is:
value=xxx
value=yyy
Use a regex approach:
re.findall(r'\bvalue=[^;]*', s)
Or - if value can be any 1+ word (letter/digit/underscore) chars:
re.findall(r'\b\w+=[^;]*', s)
See the regex demo
Details:
\b - word boundary
value= - a literal char sequence value=
[^;]* - zero or more chars other than ;.
See the Python demo:
import re
rx = re.compile(r"\bvalue=[^;]*")
s = "$%$%&^(&value=xxx;$%^$%^$&^%^*value=yyy;%$#^%"
res = rx.findall(s)
print(res)
Use regex to filter the data you want from the "junk characters":
>>> import re
>>> _input = '#4#5%value=xxx38u952035983049;3^&^*(^%$3value=yyy#%$#^&*^%;$#%$#^'
>>> matches = re.findall(r'[a-zA-Z0-9]+=[a-zA-Z0-9]+', _input)
>>> matches
['value=xxx', 'value=yyy']
>>> for match in matches:
print(match)
value=xxx
value=yyy
>>>
Summary or the regular expression:
[a-zA-Z0-9]+: One or more alphanumeric characters
=: literal equal sign
[a-zA-Z0-9]+: One or more alphanumeric characters
For this input:
content = '(random_garbage_char_here)**value=xxx**;(random_garbage_char_here)**value=yyy**;(random_garbage_char_here)'
use a simple regex and manually strip off the first and last two characters:
import re
values = [x[2:-2] for x in re.findall(r'\*\*value=.*?\*\*', content)]
for value in values:
print(value)
Output:
value=xxx
value=yyy
Here the assumption is that there are always two leading and two trailing * as in **value=xxx**.
You already have good answers based on the re module. That would certainly be the simplest way.
If for any reason (perfs?) you prefere to use str methods, it is indeed possible. But you must search the second string past the end of the first one :
value2_start = content.find('value', value1_end)
value2_end = content.find(';', value2_start)

Regular Expression (find matching characters in order)

Let us say that I have the following string variables:
welcome = "StackExchange 2016"
string_to_find = "Sx2016"
Here, I want to find the string string_to_find inside welcome using regular expressions. I want to see if each character in string_to_find comes in the same order as in welcome.
For instance, this expression would evaluate to True since the 'S' comes before the 'x' in both strings, the 'x' before the '2', the '2' before the 0, and so forth.
Is there a simple way to do this using regex?
Your answer is rather trivial. The .* character combination matches 0 or more characters. For your purpose, you would put it between all characters in there. As in S.*x.*2.*0.*1.*6. If this pattern is matched, then the string obeys your condition.
For a general string you would insert the .* pattern between characters, also taking care of escaping special characters like literal dots, stars etc. that may otherwise be interpreted by regex.
This function might fit your need
import re
def check_string(text, pattern):
return re.match('.*'.join(pattern), text)
'.*'.join(pattern) create a pattern with all you characters separated by '.*'. For instance
>> ".*".join("Sx2016")
'S.*x.*2.*0.*1.*6'
Use wildcard matches with ., repeating with *:
expression = 'S.*x.*2.*0.*1.*6'
You can also assemble this expression with join():
expression = '.*'.join('Sx2016')
Or just find it without a regular expression, checking whether the location of each of string_to_find's characters within welcome proceeds in ascending order, handling the case where a character in string_to_find is not present in welcome by catching the ValueError:
>>> welcome = "StackExchange 2016"
>>> string_to_find = "Sx2016"
>>> try:
... result = [welcome.index(c) for c in string_to_find]
... except ValueError:
... result = None
...
>>> print(result and result == sorted(result))
True
Actually having a sequence of chars like Sx2016 the pattern that best serve your purpose is a more specific:
S[^x]*x[^2]*2[^0]*0[^1]*1[^6]*6
You can obtain this kind of check defining a function like this:
import re
def contains_sequence(text, seq):
pattern = seq[0] + ''.join(map(lambda c: '[^' + c + ']*' + c, list(seq[1:])))
return re.search(pattern, text)
This approach add a layer of complexity but brings a couple of advantages as well:
It's the fastest one because the regex engine walk down the string only once while the dot-star approach go till the end of the sequence and back each time a .* is used. Compare on the same string (~1k chars):
Negated class -> 12 steps
Dot star -> 4426 step
It works on multiline strings in input as well.
Example code
>>> sequence = 'Sx2016'
>>> inputs = ['StackExchange2015','StackExchange2016','Stack\nExchange\n2015','Stach\nExchange\n2016']
>>> map(lambda x: x + ': yes' if contains_sequence(x,sequence) else x + ': no', inputs)
['StackExchange2015: no', 'StackExchange2016: yes', 'Stack\nExchange\n2015: no', 'Stach\nExchange\n2016: yes']

Using parentheses as delimiter in re or str.split() python

I am trying to split a string such as: add(ten)sub(one) into add(ten) sub(one).
I can't figure out how to match the close parentheses. I have used re.sub(r'\\)', '\\) ') and every variation of escaping the parentheses,I can think of. It is hard to tell in this font but I am trying to add a space between these commands so I can split it into a list later.
There's no need to escape ) in the replacement string, ) has a special a special meaning only in the regex pattern so it needs to be escaped there in order to match it in the string, but in normal string it can be used as is.
>>> strs = "add(ten)sub(one)"
>>> re.sub(r'\)(?=\S)',r') ', strs)
'add(ten) sub(one)'
As #StevenRumbalski pointed out in comments the above operation can be simply done using str.replace and str.rstrip:
>>> strs.replace(')',') ').strip()
'add(ten) sub(one)'
d = ')'
my_str = 'add(ten)sub(one)'
result = [t+d for t in my_str.split(d) if len(t) > 0]
result = ['add(ten)','sub(one)']
Create a list of all substrings
import re
a = 'add(ten)sub(one)'
print [ b for b in re.findall('(.+?\(.+?\))', a) ]
Output:
['add(ten)', 'sub(one)']

How do I extract some string from a long string in Python?

I have a lot of long strings - not all of them have the same length and content, so that's why I can't use indices - and I want to extract a string from all of them. This is what I want to extract:
http://www.someDomainName.com/anyNumber
SomeDomainName doesn't contain any numbers and and anyNumber is different in each long string. The code should extract the desired string from any string possible and should take into account spaces and any other weird thing that might appear in the long string - should be possible with regex right? -. Could anybody help me with this? Thank you.
Update: I should have said that www. and .com are always the same. Also someDomainName! But there's another http://www. in the string
import re
results = re.findall(r'\bhttp://www\.someDomainName\.com/\d+\b', long_string)
>>> import re
>>> pattern = re.compile("(http://www\\.)(\\w*)(\\.com/)(\\d+)")
>>> matches = pattern.search("http://www.someDomainName.com/2134")
>>> if matches:
print matches.group(0)
print matches.group(1)
print matches.group(2)
print matches.group(3)
print matches.group(4)
http://www.someDomainName.com/2134
http://www.
someDomainName
.com/
2134
In the above pattern, we have captured 5 groups -
One is the complete string that is matched
Rest are in the order of the brackets you see.. (So, you are looking for the second one..) - (\\w*)
If you want, you can capture only the part of the string you are interested in.. So, you can remove the brackets from rest of the pattern that you don't want and just keep (\w*)
>>> pattern = re.compile("http://www\\.(\\w*)\\.com/\\d+")
>>> matches = patter.search("http://www.someDomainName.com/2134")
>>> if matches:
print matches.group(1)
someDomainName
In the above example, you won't have groups - 2, 3 and 4, as in the previous example, as we have captured only 1 group.. And yes group 0 is always captured.. That is the complete string that matches..
Yeah, your simplest bet is regex. Here's something that will probably get the job done:
import re
matcher = re.compile(r'www.(.+).com\/(.+)
matches = matcher.search(yourstring)
if matches:
str1,str2 = matches.groups()
If you are sure that there are no dots in SomeDomainName you can just take the first occurence of the string ".com/" and take everything from that index on
this will avoid you the use of regex which are harder to maintain
exp = 'http://www.aejlidjaelidjl.com/alieilael'
print exp[exp.find('.com/')+5:]

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