Related
eg
Arun,Mishra,108,23,34,45,56,Mumbai
o\p I want is
Arun,Mishra,108.23,34,45,56,Mumbai
Tried to replace the comma with dot but all the demiliters are replaced with comma
tried text.replace(',','.') but replacing all the commas with dot
You can use regex for these kind of tasks:
import re
old_str = 'Arun,Mishra,108,23,34,45,56,Mumbai'
new_str = re.sub(r'(\d+)(,)(\d+)', r'\1.\3', old_str, 1)
>>> 'Arun,Mishra,108.23,34,45,56,Mumbai'
The search pattern r'(\d+)(,)(\d+)' was to find a comma between two numbers. There are three capture groups, therefore one can use them in the replacement: r\1.\3 (\1 and \3 are first and third groups). The old_str is the string and 1 is to tell the pattern to only replace the first occurrence (thus keep 34, 45).
It may be instructive to show how this can be done without additional module imports.
The idea is to search the string for all/any commas. Once the index of a comma has been identified, examine the characters either side (checking for digits). If such a pattern is observed, modify the string accordingly
s = 'Arun,Mishra,108,23,34,45,56,Mumbai'
pos = 1
while (pos := s.find(',', pos, len(s)-1)) > 0:
if s[pos-1].isdigit() and s[pos+1].isdigit():
s = s[:pos] + '.' + s[pos+1:]
break
pos += 1
print(s)
Output:
Arun,Mishra,108.23,34,45,56,Mumbai
Assuming you have a plain CSV file as in your single line example, we can assume there are 8 columns and you want to 'merge' columns 3 and 4 together. You can do this with a regular expression - as shown below.
Here I explicitly match the 8 columns into 8 groups - matching everything that is not a comma as a column value and then write out the 8 columns again with commas separating all except columns 3 and 4 where I put the period/dot you require.
$ echo "Arun,Mishra,108,23,34,45,56,Mumbai" | sed -r "s/([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*)/\1,\2,\3.\4,\5,\6,\7,\8/"
Arun,Mishra,108.23,34,45,56,Mumbai
This regex is for your exact data. Having a generic regex to replace any comma between two subsequent sets of digits might give false matches on other data however so I think explicitly matching the data based on the exact columns you have will be the safest way to do it.
You can take the above regex and code it into your python code as shown below.
import re
inLine = 'Arun,Mishra,108,23,34,45,56,Mumbai'
outLine = re.sub(r'([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*),([^,]*)'
, r'\1,\2,\3.\4,\5,\6,\7,\8', inLine, 0)
print(outLine)
As Tim Biegeleisen pointed out in an original comment, if you have access to the original source data you would be better fixing the formatting there. Of course that is not always possible.
First split the string using s.split() and then replace ',' in 2nd element
after replacing join the string back again.
s= 'Arun,Mishra,108,23,34,45,56,Mumbai '
ls = s.split(',')
ls[2] = '.'.join([ls[2], ls[3]])
ls.pop(3)
s = ','.join(ls)
It changes all the commas to dots if dot have numbers before and after itself.
txt = "2459,12 is the best number. lets change the dots . with commas , 458,45."
commaindex = 0
while commaindex != -1:
commaindex = txt.find(",",commaindex+1)
if txt[commaindex-1].isnumeric() and txt[commaindex+1].isnumeric():
txt = txt[0:commaindex] + "." + txt[commaindex+1:len(txt)+1]
print(txt)
I have a String from which I want to take the values within the parenthesis. Then, get the values that are separated from a comma.
Example: x(142,1,23ERWA31)
I would like to get:
142
1
23ERWA31
Is it possible to get everything with one regex?
I have found a method to do so, but it is ugly.
This is how I did it in python:
import re
string = "x(142,1,23ERWA31)"
firstResult = re.search("\((.*?)\)", string)
secondResult = re.search("(?<=\()(.*?)(?=\))", firstResult.group(0))
finalResult = [x.strip() for x in secondResult.group(0).split(',')]
for i in finalResult:
print(i)
142
1
23ERWA31
This works for your example string:
import re
string = "x(142,1,23ERWA31)"
l = re.findall (r'([^(,)]+)(?!.*\()', string)
print (l)
Result: a plain list
['142', '1', '23ERWA31']
The expression matches a sequence of characters not in (,,,) and – to prevent the first x being picked up – may not be followed by a ( anywhere further in the string. This makes it also work if your preamble x consists of more than a single character.
findall rather than search makes sure all items are found, and as a bonus it returns a plain list of the results.
You can make this a lot simpler. You are running your first Regex but then not taking the result. You want .group(1) (inside the brackets), not .group(0) (the whole match). Once you have that you can just split it on ,:
import re
string = "x(142,1,23ERWA31)"
firstResult = re.search("\((.*?)\)", string)
for e in firstResult.group(1).split(','):
print(e)
A little wonky looking, and also assuming there's always going to be a grouping of 3 values in the parenthesis - but try this regex
\((.*?),(.*?),(.*?)\)
To extract all the group matches to a single object - your code would then look like
import re
string = "x(142,1,23ERWA31)"
firstResult = re.search("\((.*?),(.*?),(.*?)\)", string).groups()
You can then call the firstResult object like a list
>> print(firstResult[2])
23ERWA31
I am trying to extract some groups of data from a text and validate if the input text is correct. In the simplified form my input text looks like this:
Sample=A,B;C,D;E,F;G,H;I&other_text
In which A-I are groups I am interested in extracting them.
In the generic form, Sample looks like this:
val11,val12;val21,val22;...;valn1,valn2;final_val
arbitrary number of comma separated pairs which are separated by semicolon, and one single value at the very end.
There must be at least two pairs before the final value.
The regular expression I came up with is something like this:
r'Sample=(\w),(\w);(\w),(\w);((\w),(\w);)*(\w)'
Assuming my desired groups are simply words (in reality they are more complex but this is out of the scope of the question).
It actually captures the whole text but fails to group the values correctly.
I am just assuming that your "values" are any composed of any characters other than , and ;, i.e. [^,;]+. This clearly needs to be modified in the re.match and re.finditer calls to meet your actual requirements.
import re
s = 'Sample=val11,val12;val21,val22;val31,val32;valn1,valn2;final_val'
# verify if there is a match:
m = re.match(r'^Sample=([^,;]+),+([^,;]+)(;([^,;]+),+([^,;]+))+;([^,;]+)$', s)
if m:
final_val = m.group(6)
other_vals = [(m.group(1), m.group(2)) for m in re.finditer(r'([^,;]+),+([^,;]+)', s[7:])]
print(final_val)
print(other_vals)
Prints:
final_val
[('val11', 'val12'), ('val21', 'val22'), ('val31', 'val32'), ('valn1', 'valn2')]
You can do this with a regex that has an OR in it to decide which kind of data you are parsing. I spaced out the regex for commenting and clarity.
data = 'val11,val12;val21,val22;valn1,valn2;final_val'
pat = re.compile(r'''
(?P<pair> # either comma separated ending in semicolon
(?P<entry_1>[^,;]+) , (?P<entry_2>[^,;]+) ;
)
| # OR
(?P<end_part> # the ending token which contains no comma or semicolon
[^;,]+
)''', re.VERBOSE)
results = []
for match in pat.finditer(data):
if match.group('pair'):
results.append(match.group('entry_1', 'entry_2'))
elif match.group('end_part'):
results.append(match.group('end_part'))
print(results)
This results in:
[('val11', 'val12'), ('val21', 'val22'), ('valn1', 'valn2'), 'final_val']
You can do this without using regex, by using string.split.
An example:
words = map(lambda x : x.split(','), 'val11,val12;val21,val22;valn1,valn2;final_val'.split(';'))
This will result in the following list:
[
['val11', 'val12'],
['val21', 'val22'],
['valn1', 'valn2'],
['final_val']
]
I have some data stored as pandas data frame and one of the columns contains text strings in Korean. I would like to process each of these text strings as follows:
my_string = '모질상태불량(피부상태불량, 심하게 야윔), 치석심함, 양측 수정체 백탁, 좌측 화농성 눈곱심함(7/22), 코로나음성(활력저하)'
Into a list like this:
parsed_text = '모질상태불량, 피부상태불량, 심하게 야윔, 치석심함, 양측 수정체 백탁, 좌측 화농성 눈곱심함(7/22), 코로나음성, 활력저하'
So the problem is to identify cases where a word (or several words) are followed by parentheses with text only (can be one words or several words separated by commas) and replace them by all the words (before and inside parentheses) separated by comma (for later processing). If a word is followed by parentheses containing numbers (as in this case 7/22), it should be kept as it is. If a word is not followed by any parentheses, it should also be kept as it is. Furthermore, I would like to preserve the order of words (as they appeared in the original string).
I can extract text in parentheses by using regex as follows:
corrected_string = re.findall(r'(\w+)\((\D.*?)\)', my_string)
which yields this:
[('모질상태불량', '피부상태불량, 심하게 야윔'), ('코로나음성', '활력저하')]
But I'm having difficulty creating my resulting string, i.e. replacing my original text with the pattern I've matched. Any suggestions? Thank you.
You can use re.findall with a pattern that optionally matches a number enclosed in parentheses:
corrected_string = re.findall(r'[^,()]+(?:\([^)]*\d[^)]*\))?', my_string)
It's little bit clumsy but you can try:
my_string_list = [x.strip() for x in re.split(r"\((?!\d)|(?<!\d)\)|,", my_string) if x]
# you can make string out of list then.
Consider an input string :
mystr = "just some stupid string to illustrate my question"
and a list of strings indicating where to split the input string:
splitters = ["some", "illustrate"]
The output should look like
result = ["just ", "some stupid string to ", "illustrate my question"]
I wrote some code which implements the following approach. For each of the strings in splitters, I find its occurrences in the input string, and insert something which I know for sure would not be a part of my input string (for example, this '!!'). Then I split the string using the substring that I just inserted.
for s in splitters:
mystr = re.sub(r'(%s)'%s,r'!!\1', mystr)
result = re.split('!!', mystr)
This solution seems ugly, is there a nicer way of doing it?
Splitting with re.split will always remove the matched string from the output (NB, this is not quite true, see the edit below). Therefore, you must use positive lookahead expressions ((?=...)) to match without removing the match. However, re.split ignores empty matches, so simply using a lookahead expression doesn't work. Instead, you will lose one character at each split at minimum (even trying to trick re with "boundary" matches (\b) does not work). If you don't care about losing one whitespace / non-word character at the end of each item (assuming you only split at non-word characters), you can use something like
re.split(r"\W(?=some|illustrate)")
which would give
["just", "some stupid string to", "illustrate my question"]
(note that the spaces after just and to are missing). You could then programmatically generate these regexes using str.join. Note that each of the split markers is escaped with re.escape so that special characters in the items of splitters do not affect the meaning of the regular expression in any undesired ways (imagine, e.g., a ) in one of the strings, which would otherwise lead to a regex syntax error).
the_regex = r"\W(?={})".format("|".join(re.escape(s) for s in splitters))
Edit (HT to #Arkadiy): Grouping the actual match, i.e. using (\W) instead of \W, returns the non-word characters inserted into the list as seperate items. Joining every two subsequent items would then produce the list as desired as well. Then, you can also drop the requirement of having a non-word character by using (.) instead of \W:
the_new_regex = r"(.)(?={})".format("|".join(re.escape(s) for s in splitters))
the_split = re.split(the_new_regex, mystr)
the_actual_split = ["".join(x) for x in itertools.izip_longest(the_split[::2], the_split[1::2], fillvalue='')]
Because normal text and auxiliary character alternate, the_split[::2] contains the normal split text and the_split[1::2] the auxiliary characters. Then, itertools.izip_longest is used to combine each text item with the corresponding removed character and the last item (which is unmatched in the removed characters)) with fillvalue, i.e. ''. Then, each of these tuples is joined using "".join(x). Note that this requires itertools to be imported (you could of course do this in a simple loop, but itertools provides very clean solutions to these things). Also note that itertools.izip_longest is called itertools.zip_longest in Python 3.
This leads to further simplification of the regular expression, because instead of using auxiliary characters, the lookahead can be replaced with a simple matching group ((some|interesting) instead of (.)(?=some|interesting)):
the_newest_regex = "({})".format("|".join(re.escape(s) for s in splitters))
the_raw_split = re.split(the_newest_regex, mystr)
the_actual_split = ["".join(x) for x in itertools.izip_longest([""] + the_raw_split[1::2], the_raw_split[::2], fillvalue='')]
Here, the slice indices on the_raw_split have swapped, because now the even-numbered items must be added to item afterwards instead of in front. Also note the [""] + part, which is necessary to pair the first item with "" to fix the order.
(end of edit)
Alternatively, you can (if you want) use string.replace instead of re.sub for each splitter (I think that is a matter of preference in your case, but in general it is probably more efficient)
for s in splitters:
mystr = mystr.replace(s, "!!" + s)
Also, if you use a fixed token to indicate where to split, you do not need re.split, but can use string.split instead:
result = mystr.split("!!")
What you could also do (instead of relying on the replacement token not to be in the string anywhere else or relying on every split position being preceded by a non-word character) is finding the split strings in the input using string.find and using string slicing to extract the pieces:
def split(string, splitters):
while True:
# Get the positions to split at for all splitters still in the string
# that are not at the very front of the string
split_positions = [i for i in (string.find(s) for s in splitters) if i > 0]
if len(split_positions) > 0:
# There is still somewhere to split
next_split = min(split_positions)
yield string[:next_split] # Yield everything before that position
string = string[next_split:] # Retain the rest of the string
else:
yield string # Yield the rest of the string
break # Done.
Here, [i for i in (string.find(s) for s in splitters) if i > 0] generates a list of positions where the splitters can be found, for all splitters that are in the string (for this, i < 0 is excluded) and not right at the beginning (where we (possibly) just split, so i == 0 is excluded as well). If there are any left in the string, we yield (this is a generator function) everything up to (excluding) the first splitter (at min(split_positions)) and replace the string with the remaining part. If there are none left, we yield the last part of the string and exit the function. Because this uses yield, it is a generator function, so you need to use list to turn it into an actual list.
Note that you could also replace yield whatever with a call to some_list.append (provided you defined some_list earlier) and return some_list at the very end, I do not consider that to be very good code style, though.
TL;DR
If you are OK with using regular expressions, use
the_newest_regex = "({})".format("|".join(re.escape(s) for s in splitters))
the_raw_split = re.split(the_newest_regex, mystr)
the_actual_split = ["".join(x) for x in itertools.izip_longest([""] + the_raw_split[1::2], the_raw_split[::2], fillvalue='')]
else, the same can also be achieved using string.find with the following split function:
def split(string, splitters):
while True:
# Get the positions to split at for all splitters still in the string
# that are not at the very front of the string
split_positions = [i for i in (string.find(s) for s in splitters) if i > 0]
if len(split_positions) > 0:
# There is still somewhere to split
next_split = min(split_positions)
yield string[:next_split] # Yield everything before that position
string = string[next_split:] # Retain the rest of the string
else:
yield string # Yield the rest of the string
break # Done.
Not especially elegant but avoiding regex:
mystr = "just some stupid string to illustrate my question"
splitters = ["some", "illustrate"]
indexes = [0] + [mystr.index(s) for s in splitters] + [len(mystr)]
indexes = sorted(list(set(indexes)))
print [mystr[i:j] for i, j in zip(indexes[:-1], indexes[1:])]
# ['just ', 'some stupid string to ', 'illustrate my question']
I should acknowledge here that a little more work is needed if a word in splitters occurs more than once because str.index finds only the location of the first occurrence of the word...