I've seen a lot of examples on how to remove brackets from a string in Python, but I've not seen any that allow me to remove the brackets and a number inside of the brackets from that string.
For example, suppose I've got a string such as "abc[1]". How can I remove the "[1]" from the string to return just "abc"?
I've tried the following:
stringTest = "abc[1]"
stringTestWithoutBrackets = str(stringTest).strip('[]')
but this only outputs the string without the final bracket
abc[1
I've also tried with a wildcard option:
stringTest = "abc[1]"
stringTestWithoutBrackets = str(stringTest).strip('[\w+\]')
but this also outputs the string without the final bracket
abc[1
You could use regular expressions for that, but I think the easiest way would be to use split:
>>> stringTest = "abc[1][2][3]"
>>> stringTest.split('[', maxsplit=1)[0]
'abc'
You can use regex but you need to use it with the re module:
re.sub(r'\[\d+\]', '', stringTest)
If the [<number>] part is always at the end of the string you can also strip via:
stringTest.rstrip('[0123456789]')
Though the latter version might strip beyond the [ if the previous character is in the strip list too. For example in "abc1[5]" the "1" would be stripped as well.
Assuming your string has the format "text[number]" and you only want to keep the "text", then you could do:
stringTest = "abc[1]"
bracketBegin = stringTest.find('[')
stringTestWithoutBrackets = stringTest[:bracketBegin]
Related
I have a string as follows where I tried to remove similar consecutive characters.
import re
input = "abccbcbbb";
for i in input :
input = re.sub("(.)\\1+", "",input);
print(input)
Now I need to let the user specify the value of k.
I am using the following python code to do it, but I got the error message TypeError: can only concatenate str (not "int") to str
import re
input = "abccbcbbb";
k=3
for i in input :
input= re.sub("(.)\\1+{"+(k-1)+"}", "",input)
print(input)
The for i in input : does not do what you need. i is each character in the input string, and your re.sub is supposed to take the whole input as a char sequence.
If you plan to match a specific amount of chars you should get rid of the + quantifier after \1. The limiting {min,} / {min,max} quantifier should be placed right after the pattern it modifies.
Also, it is more convenient to use raw string literals when defining regexps.
You can use
import re
input_text = "abccbcbbb";
k=3
input_text = re.sub(fr"(.)\1{{{k-1}}}", "", input_text)
print(input_text)
# => abccbc
See this Python demo.
The fr"(.)\1{{{k-1}}}" raw f-string literal will translate into (.)\1{2} pattern. In f-strings, you need to double curly braces to denote a literal curly brace and you needn't escape \1 again since it is a raw string literal.
If I were you, I would prefer to do it like suggested before. But since I've already spend time on answering this question here is my handmade solution.
The pattern described below creates a named group named "letter". This group updates iterative, so firstly it is a, then b, etc. Then it looks ahead for all the repetitions of the group "letter" (which updates for each letter).
So it finds all groups of repeated letters and replaces them with empty string.
import re
input = 'abccbcbbb'
result = 'abcbcb'
pattern = r'(?P<letter>[a-z])(?=(?P=letter)+)'
substituted = re.sub(pattern, '', input)
assert substituted == result
Just to make sure I have the question correct you mean to turn "abccbcbbb" into "abcbcb" only removing sequential duplicate characters. Is there a reason you need to use regex? you could likely do a simple list comprehension. I mean this is a really cut and dirty way to do it but you could just put
input = "abccbcbbb"
input = list(input)
previous = input.pop(0)
result = [previous]
for letter in input:
if letter != previous : result += letter
previous = letter
result = "".join(result)
and with a method like this, you could make it easier to read and faster with a bit of modification id assume.
So I have the following strings and I have been trying to figure out how to manipulate them in such a way that I get a specific format.
string1-itd_jan2021-internal
string2itd_mar2021-space
string3itd_feb2021-internal
string4-itd_mar2021-moon
string5itd_jun2021-internal
string6-itd_feb2021-apollo
I want to be able to get rid of any of the last string so I am just left with the month and year, like below:
string1-itd_jan2021
string2itd_mar2021
string3itd_feb2021
string4-itd_mar2021
string5itd_jun2021
string6-itd_feb2021
I thought about using string.split on the - but then realized that for some strings this wouldn't work. I also thought about getting rid of a set amount of characters by putting it into a list and slicing but the end is varying characters length?
Is there anything I can do it with regex or any other python module?
Use str.rsplit with the appropriate maxsplit parameter:
s = s.rsplit("-", 1)[0]
You could also use str.split (even though this is clearly the worse choice):
s = "-".join(s.split("-")[:-1])
Or using regular expressions:
s = re.sub(r'-[^-]*$', '', s)
# "-[^-]*" a "-" followed by any number of non-"-"
With a regex:
import re
re.sub(r'([0-9]{4}).*$', r'\1', s)
Use re.sub like so:
import re
lines = '''string1-itd_jan2021-internal
string2itd_mar2021-space
string3itd_feb2021-internal
string4-itd_mar2021-moon
string5itd_jun2021-internal
string6-itd_feb2021-apollo'''
for old in lines.split('\n'):
new = re.sub(r'[-][^-]+$', '', old)
print('\t'.join([old, new]))
Prints:
string1-itd_jan2021-internal string1-itd_jan2021
string2itd_mar2021-space string2itd_mar2021
string3itd_feb2021-internal string3itd_feb2021
string4-itd_mar2021-moon string4-itd_mar2021
string5itd_jun2021-internal string5itd_jun2021
string6-itd_feb2021-apollo string6-itd_feb2021
Explanation:
r'[-][^-]+$' : Literal dash (-), followed by any character other than a dash ([^-]) repeated 1 or more times, followed by the end of the string ($).
Lets say I have a bunch of strings, and they can only be in the following formats:
format1 = 'substring1#substring2'
format2 = 'substring1$substring2'
format3 = 'substring1'
Let me explain. The strings are sometimes divided using the # or $ character. However other times, they are not.
I want to remove the part that appears after the # or $, if it exists. If it was just one special character, that is #, I could have done this:
string = string.split('#')[0]
But how can I do it for the 2 special characters in a quick and elegant way? Also assume the following things:
Only one special character can appear in the string.
The special characters will not appear in any other part of the string.
Thanks.
If you want to avoid regex, one possibility would be:
string = min(string.split('#')[0], string.split('$')[0])
Regular expressions.
import re
re.sub('[$#].*', '', string_to_modify)
Use regex!
import re
new_string = re.sub(r"(#|$).*$", "", string)
Use re.split() for it.
import re
print(re.split("#|$","STRING#OTHER_STRING#OTHER_STRING_2"))
Use replace before split:
format1 = 'substring1#substring2'
format2 = 'substring1$substring2'
format3 = 'substring1'
print(format1.replace('#', '$').split('$')[0])
print(format2.replace('#', '$').split('$')[0])
print(format3.replace('#', '$').split('$')[0])
Output
substring1
substring1
substring1
You can use a for loop to split by an arbitrary number of delimiters. Regular expression is typically less efficient than Python str methods.
def converter(x, delims='#$'):
for delim in delims:
x = x.split(delim, maxsplit=1)[0]
return x
format1 = 'substring1#substring2'
format2 = 'substring1$substring2'
format3 = 'substring1'
for value in [format1, format2, format3]:
print(converter(value))
# substring1
# substring1
# substring1
I think you can use a list to maintain the special characters that can be used and for every of them check if is present in the string, when you find one execute the splitting process and retrieve only the left part like so:
delimters = ["#","$"]
for symbol in delimters:
if symbol in string1:
left_part = string1.split(symbol)[0]
Now this approach has some disadvantages but is the simplest in my opinion. The problem is that if you have more than one string you need to nested loops.
a = "\Virtual Disks\DG2_ASM04\ACTIVE"
From the above string I would like to get the part "DG2_ASM04" alone. I cannot split or strip as it has the special characters "\", "\D" and "\A" in it.
Have tried the below and can't get the desired output.
a.lstrip("\Virtual Disks\\").rstrip("\ACTIVE")
the output I have got is: 'G2_ASM04' instead of "DG2_ASM04"
Simply use slicing and escape backslash(\)
>>> a.split("\\")[-2]
'DG2_ASM04'
In your case D is also removing because it is occurring more than one time in given string (thus striping D as well). If you tweak your string then you will realize what is happening
>>> a = "\Virtual Disks\XG2_ASM04\ACTIVE"
>>> a.lstrip('\\Virtual Disks\\').rstrip("\\ACTIVE")
'XG2_ASM04'
Have a set of string as follows
text:u'MUC-EC-099_SC-Memory-01_TC-25'
text:u'MUC-EC-099_SC-Memory-01_TC-26'
text:u'MUC-EC-099_SC-Memory-01_TC-27'
These data i have extracted from a Xls file and converted to string,
now i have to Extract data which is inside single quotes and put them in a list.
expecting output like
[MUC-EC-099_SC-Memory-01_TC-25, MUC-EC-099_SC-Memory-01_TC-26,MUC-EC-099_SC-Memory-01_TC-27]
Thanks in advance.
Use re.findall:
>>> import re
>>> strs = """text:u'MUC-EC-099_SC-Memory-01_TC-25'
text:u'MUC-EC-099_SC-Memory-01_TC-26'
text:u'MUC-EC-099_SC-Memory-01_TC-27'"""
>>> re.findall(r"'(.*?)'", strs, re.DOTALL)
['MUC-EC-099_SC-Memory-01_TC-25',
'MUC-EC-099_SC-Memory-01_TC-26',
'MUC-EC-099_SC-Memory-01_TC-27'
]
You can use the following expression:
(?<=')[^']+(?=')
This matches zero or more characters that are not ' which are enclosed between ' and '.
Python Code:
quoted = re.compile("(?<=')[^']+(?=')")
for value in quoted.findall(str(row[1])):
i.append(value)
print i
That text: prefix seems a little familiar. Are you using xlrd to extract it? In that case, the reason you have the prefix is because you're getting the wrapped Cell object, not the value in the cell. For example, I think you're doing something like
>>> sheet.cell(2,2)
number:4.0
>>> sheet.cell(3,3)
text:u'C'
To get the unwrapped object, use .value:
>>> sheet.cell(3,3).value
u'C'
(Remember that the u here is simply telling you the string is unicode; it's not a problem.)