I want to write a script that reads from a csv file and splits each line by comma except any commas in-between two specific characters.
In the below code snippet I would like to split line by commas except the commas in-between two $s.
line = "$abc,def$,$ghi$,$jkl,mno$"
output = line.split(',')
for o in output:
print(o)
How do I write output = line.split(',') so that I get the following terminal output?
~$ python script.py
$abc,def$
$ghi$
$jkl,mno$
You can do this with a regular expression:
In re, the (?<!\$) will match a character not immediately following a $.
Similarly, a (?!\$) will match a character not immediately before a dollar.
The | character cam match multiple options. So to match a character where either side is not a $ you can use:
expression = r"(?<!\$),|,(?!\$)"
Full program:
import re
expression = r"(?<!\$),|,(?!\$)"
print(re.split(expression, "$abc,def$,$ghi$,$jkl,mno$"))
One solution (maybe not the most elegant but it will work) is to replace the string $,$ with something like $,,$ and then split ,,. So something like this
output = line.replace('$,$','$,,$').split(',,')
Using regex like mousetail suggested is the more elegant and robust solution but requires knowing regex (not that anyone KNOWS regex)
Try regular expressions:
import re
line = "$abc,def$,$ghi$,$jkl,mno$"
output = re.findall(r"\$(.*?)\$", line)
for o in output:
print('$'+o+'$')
$abc,def$
$ghi$
$jkl,mno$
First, you can identify a character that is not used in that line:
c = chr(max(map(ord, line)) + 1)
Then, you can proceed as follows:
line.replace('$,$', f'${c}$').split(c)
Here is your example:
>>> line = '$abc,def$,$ghi$,$jkl,mno$'
>>> c = chr(max(map(ord, line)) + 1)
>>> result = line.replace('$,$', f'${c}$').split(c)
>>> print(*result, sep='\n')
$abc,def$
$ghi$
$jkl,mno$
Related
I am trying to split the string with python code with following output:
import os
f = "Retirement-User-Portfolio-DEV-2020-7-29.xml"
to_output = os.path.splitext(f)[0]
print(to_output)
I have received an output :
Retirement-User-Portfolio-DEV-2020-7-29
However, I want the output like this below and remove "-DEV-2020-7-29" FROM THE STRING:
Retirement-User-Portfolio
You can use split() and join() to split on the kth occurrence of a character.
f = "Retirement-User-Portfolio-DEV-2020-7-29.xml"
to_output = '-'.join(f.split('-')[0:3])
You should explain your question more with details on the pattern you are trying to match - is it always the third character? Other solutions (e.g., regex) may be more appropriate.
Try this code -
f = "Retirement-User-Portfolio-DEV-2020-7-29.xml"
a = f.split('-')
print('-'.join(a[:3]))
Looking for some alternative to clean a tabular file containing informations between parenthesis.
It will be the first step to include in a pipeline and I need to remove every value inside parenthesis (parenthesis included).
What I have
> Otu00467 Bacteria(100);Gracilibacteria(99);unclassified(99);unclassified(99);unclassified(99);unclassified(99);
> Otu00469 Bacteria(100);Proteobacteria(96);unclassified(96);unclassified(96);unclassified(96);unclassified(96);
> Otu00470 Bacteria(100);Proteobacteria(100);Alphaproteobacteria(100);Rhodospirillales(100);Rhodospirillaceae(100);Azospirillum(54);
What I desire:
Otu00467 Bacteria;Gracilibacteria;unclassified;unclassified;unclassified;unclassified;
Otu00469 Bacteria;Proteobacteria;unclassified;unclassified;unclassified;unclassified;
Otu00470 Bacteria;Proteobacteria;Alphaproteobacteria;Rhodospirillales;Rhodospirillaceae;Azospirillum;
My first approach was to split the second column by ";" , "(" , ")" and further join everything. Not bad but too ugly.
Thank you.
import re
new_string = re.sub(r'\(.*?\)', '', your_string)
I would try regexp for it. Something like that:
pattern = re.compile('(\w+)\(\d+\);')
';'.join(re.findall(pattern, string))
For each string
This regex gets rid of parenthesized groups of digits, it also gets rid of any '>' characters, since it appears that you want to eliminate them as well.
import re
data = '''\
> Otu00467 Bacteria(100);Gracilibacteria(99);unclassified(99);>unclassified(99);unclassified(99);unclassified(99);
> Otu00469 Bacteria(100);Proteobacteria(96);unclassified(96);unclassified(96);unclassified(96);unclassified(96);
> Otu00470 Bacteria(100);Proteobacteria(100);Alphaproteobacteria(100);Rhodospirillales(100);Rhodospirillaceae(100);Azospirillum(54);
'''
data = re.sub(r'>|\(\d+\)', '', data)
print(data)
output
Otu00467 Bacteria;Gracilibacteria;unclassified;unclassified;unclassified;unclassified;
Otu00469 Bacteria;Proteobacteria;unclassified;unclassified;unclassified;unclassified;
Otu00470 Bacteria;Proteobacteria;Alphaproteobacteria;Rhodospirillales;Rhodospirillaceae;Azospirillum;
This code works on Python 2 & 3.
Use re.sub:
import re
with open open('file.txt') as file:
text = re.sub(r'\(.*?\)', '', file.read(), flags=re.M)
This removes all occurrences of the text enclosed in parentheses. The re.M flag is the multiline specifier, which is useful when your string has newlines within the matching pattern.
#Use re module to use regex
import re
#Open file and read data in data variable
data = open('file.txt').read()
#Apply search and replace on data variable
data = re.sub('\(\d+\)', '', data)
#Print data to output.txt file
with open('output.txt', 'w') as out:
out.write(data)
For example I've got a file with lines like this
\tline1\t
\t\tline2\t
\t\tline3
\tline4
I need to remove only first tab in the beginning of every string(and I don't care if there are more tabs in the line)
So the result suppose to look like this
line1\t
\tline2\t
\tline3
line4
How to do it?
s = "\thello"
s.replace("\t", "", 1)
Unsure if it's needed but this will handle stuff like `"hello\tworld" also, i.e. replace the first tab in the string disregarding where in the string it is
Regular expressions may help:
>>> import re
>>> pattern = re.compile('^\t') # match a tab in the beginning of the line
>>> pattern.sub('', '\tline1\t')
'line1\t'
>>> pattern.sub('', '\t\tline2\t')
'\tline2\t'
>>> pattern.sub('', 'line3\t')
'line3\t'
I am trying to write a regex in Python to extract some information from a string.
Given:
"Only in Api_git/Api/folder A: new.txt"
I would like to print:
Folder Path: Api_git/Api/folder A
Filename: new.txt
After having a look at some examples on the re manual page, I'm still a bit stuck.
This is what I've tried so far
m = re.match(r"(Only in ?P<folder_path>\w+:?P<filename>\w+)","Only in Api_git/Api/folder A: new.txt")
print m.group('folder_path')
print m.group('filename')
Can anybody point me in the right direction??
Get the matched group from index 1 and 2 using capturing groups.
^Only in ([^:]*): (.*)$
Here is demo
sample code:
import re
p = re.compile(ur'^Only in ([^:]*): (.*)$')
test_str = u"Only in Api_git/Api/folder A: new.txt"
re.findall(p, test_str)
If you want to print in the below format then try with substitution.
Folder Path: Api_git/Api/folder A
Filename: new.txt
DEMO
sample code:
import re
p = re.compile(ur'^Only in ([^:]*): (.*)$')
test_str = u"Only in Api_git/Api/folder A: new.txt"
subst = u"Folder Path: $1\nFilename: $2"
result = re.sub(p, subst, test_str)
Your pattern: (Only in ?P<folder_path>\w+:?P<filename>\w+) has a few flaws in it.
The ?P construct is only valid as the first bit inside a parenthesized expression,
so we need this.
(Only in (?P<folder_path>\w+):(?P<filename>\w+))
The \w character class is only for letters and underscores. It won't match / or ., for example. We need to use a different character class that more closely aligns with requirements. In fact, we can just use ., the class of nearly all characters:
(Only in (?P<folder_path>.+):(?P<filename>.+))
The colon has a space after it in your example text. We need to match it:
(Only in (?P<folder_path>.+): (?P<filename>.+))
The outermost parentheses are not needed. They aren't wrong, just not needed:
Only in (?P<folder_path>.+): (?P<filename>.+)
It is often convenient to provide the regular expression separate from the call to the regular expression engine. This is easily accomplished by creating a new variable, for example:
regex = r'Only in (?P<folder_path>.+): (?P<filename>.+)'
... # several lines later
m = re.match(regex, "Only in Api_git/Api/folder A: new.txt")
The above is purely for the convenience of the programmer: it neither saves nor squanders time or memory space. There is, however, a technique that can save some of the time involved in regular expressions: compiling.
Consider this code segment:
regex = r'Only in (?P<folder_path>.+): (?P<filename>.+)'
for line in input_file:
m = re.match(regex, line)
...
For each iteration of the loop, the regular expression engine must interpret the regular expression and apply it to the line variable. The re module allows us to separate the interpretation from the application; we can interpret once but apply several times:
regex = re.compile(r'Only in (?P<folder_path>.+): (?P<filename>.+)')
for line in input_file:
m = re.match(regex, line)
...
Now, your original program should look like this:
regex = re.compile(r'Only in (?P<folder_path>.+): (?P<filename>.+)')
m = re.match(regex, "Only in Api_git/Api/folder A: new.txt")
print m.group('folder_path')
print m.group('filename')
However, I'm a fan of using comments to explain regular expressions. My version, including some general cleanup, looks like this:
import re
regex = re.compile(r'''(?x) # Verbose
Only\ in\ # Literal match
(?P<folder_path>.+) # match longest sequence of anything, and put in 'folder_path'
:\ # Literal match
(?P<filename>.+) # match longest sequence of anything and put in 'filename'
''')
with open('diff.out') as input_file:
for line in input_file:
m = re.match(regex, line)
if m:
print m.group('folder_path')
print m.group('filename')
It really depends on the limitation of the input, if this is the only input this will do the trick.
^Only in (?P<folder_path>[a-zA-Z_/ ]*): (?P<filename>[a-z]*.txt)$
I am wanting to verify and then parse this string (in quotes):
string = "start: c12354, c3456, 34526; other stuff that I don't care about"
//Note that some codes begin with 'c'
I would like to verify that the string starts with 'start:' and ends with ';'
Afterward, I would like to have a regex parse out the strings. I tried the following python re code:
regx = r"start: (c?[0-9]+,?)+;"
reg = re.compile(regx)
matched = reg.search(string)
print ' matched.groups()', matched.groups()
I have tried different variations but I can either get the first or the last code but not a list of all three.
Or should I abandon using a regex?
EDIT: updated to reflect part of the problem space I neglected and fixed string difference.
Thanks for all the suggestions - in such a short time.
In Python, this isn’t possible with a single regular expression: each capture of a group overrides the last capture of that same group (in .NET, this would actually be possible since the engine distinguishes between captures and groups).
Your easiest solution is to first extract the part between start: and ; and then using a regular expression to return all matches, not just a single match, using re.findall('c?[0-9]+', text).
You could use the standard string tools, which are pretty much always more readable.
s = "start: c12354, c3456, 34526;"
s.startswith("start:") # returns a boolean if it starts with this string
s.endswith(";") # returns a boolean if it ends with this string
s[6:-1].split(', ') # will give you a list of tokens separated by the string ", "
This can be done (pretty elegantly) with a tool like Pyparsing:
from pyparsing import Group, Literal, Optional, Word
import string
code = Group(Optional(Literal("c"), default='') + Word(string.digits) + Optional(Literal(","), default=''))
parser = Literal("start:") + OneOrMore(code) + Literal(";")
# Read lines from file:
with open('lines.txt', 'r') as f:
for line in f:
try:
result = parser.parseString(line)
codes = [c[1] for c in result[1:-1]]
# Do something with teh codez...
except ParseException exc:
# Oh noes: string doesn't match!
continue
Cleaner than a regular expression, returns a list of codes (no need to string.split), and ignores any extra characters in the line, just like your example.
import re
sstr = re.compile(r'start:([^;]*);')
slst = re.compile(r'(?:c?)(\d+)')
mystr = "start: c12354, c3456, 34526; other stuff that I don't care about"
match = re.match(sstr, mystr)
if match:
res = re.findall(slst, match.group(0))
results in
['12354', '3456', '34526']