I am using string replace method to clean-up column names.
df.columns=df.columns.str.replace("#$%./- ","").str.replace(' ', '_').str.replace('.', '_').str.replace('(','').str.replace(')','').str.replace('.','').str.lower()
Though it works, certainly does not look pythonic. Any suggestion?
I need only A-Za-z and underscore _ if required as column names.
Update:
I tried using Regular expression in the first replace method, but I still need to chain the string like this...
terms.columns=terms.columns.str.replace(r"^[^a-zA-Z1-9]*", '').str.replace(' ', '_').str.replace('(','').str.replace(')','').str.replace('.', '').str.replace(',', '')
Update showing test data:
Original string (Tab separated):
[Sr.No. Course Terms Besic of Education Degree Course Course Approving Authority (i.e Medical Council, etc.) Full form of Course 1 year Duration 2nd year 3rd year Duration 4 th year Duration]
Change column names:
terms.columns=terms.columns.str.replace(r"^[^a-zA-Z1-9]*", '').str.replace(' ', '_').str.replace('(','').str.replace(')','').str.replace('.', '').str.replace(',', '').str.lower()
Output:
['srno', 'course', 'terms', 'besic_of_education', 'degree_course',
'course_approving_authority_ie_medical_council_etc',
'full_form_of_course', '1_year_duration', '2nd_year_',
'3rd_year_duration', '4_th_year_duration']
Above output is correct. The question: Is there any way to achive the same other than the way I have used?
You can use a smaller number of .replace operations by replacing non-word strings with an empty string and subsequently removing the whitespace characters with an underscore.
df.columns.str.replace("[^\w\s]+","").str.replace("\s+","_").str.lower()
I hope this helps.
Related
I have to replace a string pattern in SQL with empty string, could anyone please suggest me?
Input String 'AC001,AD001,AE001,SA001,AE002,SD001'
Output String 'AE001,AE002
There are the 4 digit codes with first 2 characters "alphabets" and last two are digits. This is always a 4 digit code. And I have to replace all codes except the codes starting with "AE".
I can have 0 or more instances of "AE" codes in the string. The final output should be a formatted string "separated by commas" for multiple "AE" codes as mentioned above.
Here is one option calling regex_replace multiple times, eliminating the "not required" strings little by little in each iteration to arrive at the required output.
SELECT regexp_replace(
regexp_replace(
regexp_replace(
'AC001,AD001,AE001,SA001,AE002,SD001', '(?<!AE)\d{3},{0,1}', 'X','g'
),'..X','','g'
),',$','','g'
)
See Demo here
I would convert the list to an array, unnest that to rows then filter out those that should be kept and aggregate it back to a string:
select string_agg(t, ',')
from unnest(string_to_array('AC001,AD001,AE001,SA001,AE002,SD001',',') as x(t)
where x.t like 'AE%'; --<< only keep those
This is independent of the number of elements in the string and can easily be extended to support more complex conditions.
This is a good example why storing comma separated values in a single column is not such a good idea to begin with.
I made a regex which inserts a space where ever there is any of the characters
-:\*_/;, present for example JET*AIRWAYS\INDIA/858701/IDBI 05/05/05;05:05:05 a/c should beJET* AIRWAYS\ INDIA/ 858701/ IDBI 05/05/05; 05:05:05 a/c
The regex I used is (?!a\/c|w\/d|m\/s|s\/w|m\/o)(\D-|\D:|\D\*|\D_|\D\\|\D\/|\D\;)
I have added some words exceptions like a/c w/d etc. \D conditions given to avoid date/time values getting separated, but this created an issue, the numbers followed by the above mentioned characters never get split.
My requirement is
1. Insert a space after characters -:\*_/;,
2. but date and time should not get split which may have / :
3. need exception on words like a/c w/d
The following is the full code
Private Function formatColon(oldString As String) As String
Dim reg As New RegExp: reg.Global = True: reg.Pattern = "(?!a\/c|w\/d|m\/s|s\/w|m\/o)(\D-|\D:|\D\*|\D_|\D\\|\D\/|\D\;)" '"(\D:|\D/|\D-|^w/d)"
Dim newString As String: newString = reg.Replace(oldString, "$1 ")
formatColon = XtraspaceKill(newString)
End Function
I would use 3 replacements.
Replace all date and time special characters with a special macro that should never be found in your text, e.g. for 05/15/2018 4:06 PM, something based on your name:
05MANUMOHANSLASH15MANUMOHANSLASH2018 4MANUMOHANCOLON06 PM
You can encode exceptions too, like this:
aMANUMOHANSLASHc
Now run your original regex to replace all special characters.
Finally, unreplace the macros MANUMOHANSLASH and MANUMOHANCOLON.
Meanwhile, let me tell you why this is complicated in a single regex.
If trying to do this in a single regex, you have to ask, for each / or :, "Am I a part of a date or time?"
To answer that, you need to use lookahead and lookbehind assertions, the latter of which Microsoft has finally added support for.
But given a /, you don't know if you're between the first and second, or second and third parts of the date. Similar for time.
The number of cases you need to consider will render your regex unmaintainably complex.
So please just use a few separate replacements :-)
I need to create some columns from a cell that contains text separated by "_".
The input would be:
campaign1_attribute1_whatever_yes_123421
And the output has to be in different columns (one per field), with no "_" and excluding the final number, as it follows:
campaign1 attribute1 whatever yes
It must be done using a regex formula!
help!
Thanks in advance (and sorry for my english)
=REGEXEXTRACT("campaign1_attribute1_whatever_yes_123421","(("®EXREPLACE("campaign1_attribute1_whatever_yes_123421","((_)|(\d+$))",")$1(")&"))")
What this does is replace all the _ with parenthesis to create capture groups, while also excluding the digit string at the end, then surround the whole string with parenthesis.
We then use regex extract to actuall pull the pieces out, the groups automatically push them to their own cells/columns
To solve this you can use the SPLIT and REGEXREPLACE functions
Solution:
Text - A1 = "campaign1_attribute1_whatever_yes_123421"
Formula - A3 = =SPLIT(REGEXREPLACE(A1,"_+\d*$",""), "_", TRUE)
Explanation:
In cell A3 We use SPLIT(text, delimiter, [split_by_each]), the text in this case is formatted with regex =REGEXREPLACE(A1,"_+\d$","")* to remove 123421, witch will give you a column for each word delimited by ""
A1 = "campaign1_attribute1_whatever_yes_123421"
A2 = "=REGEXREPLACE(A1,"_+\d*$","")" //This gives you : *campaign1_attribute1_whatever_yes*
A3 = SPLIT(A2, "_", TRUE) //This gives you: campaign1 attribute1 whatever yes, each in a separate column.
I finally figured it out yesterday in stackoverflow (spanish): https://es.stackoverflow.com/questions/55362/c%C3%B3mo-separo-texto-por-guiones-bajos-de-una-celda-en...
It was simple enough after all...
The reason I asked to be only in regex and for google sheets was because I need to use it in Google data studio (same regex functions than spreadsheets)
To get each column just use this regex extract function:
1st column: REGEXP_EXTRACT(Campaña, '^(?:[^_]*_){0}([^_]*)_')
2nd column: REGEXP_EXTRACT(Campaña, '^(?:[^_]*_){1}([^_]*)_')
3rd column: REGEXP_EXTRACT(Campaña, '^(?:[^_]*_){2}([^_]*)_')
etc...
The only thing that has to be changed in the formula to switch columns is the numer inside {}, (column number - 1).
If you do not have the final number, just don't put the last "_".
Lastly, remember to do all the calculated fields again, because (for example) it gets an error with CPC, CTR and other Adwords metrics that are calculated automatically.
Hope it helps!
I have a '3 x 1' cell array the contents of which appear like the following:
'ASDF_LE_NEWYORK Fixedafdfgd_ML'
'Majo_LE_WASHINGTON FixedMonuts_ML'
'Array_LE_dfgrt_fdhyuj_BERLIN Potato Price'
I want to be able to elegantly extract and create another '3x1' cell array with contents as:
'NEWYORK'
'WASHINGTON'
'BERLIN'
If you notice in above the NAME's are after the last underscore and before the first SPACE or '_ML'. How do I write such code in a concise manner.
Thanks
Edit:
Sorry guys I should have used a better example. I have it corrected now.
You can use lookbehind for _ and lookahead for space:
names = regexp(A, '(?<=_)[^\s_]*(?=\s)', 'match', 'once');
Where A is the cell array containing the strings:
A = {...
'ASDF_LE_NEWYORK Fixedafdfgd_ML'
'Majo_LE_WASHINGTON FixedMonuts_ML'
'Array_LE_dfgrt_fdhyuj_BERLIN Potato Price'};
>> names = regexp(A, '(?<=_)[^\s_]*(?=\s)', 'match', 'once')
names =
'NEWYORK'
'WASHINGTON'
'BERLIN'
NOTE: The question was changed, so the answer is no longer complete, but hopefully the regexp example is still useful.
Try regexp like this:
names = regexp(fullNamesCell,'_(NAME\d?)\s','tokens');
names = cellfun(#(x)(x{1}),names)
In the pattern _(NAME\d?)\s, the parenthesis define a subexpression, which will be returned as a token (a portion of matched text). The \d? specifies zero or one digits, but you could use \d{1} for exactly one digit or \d{1,3} if you expect between 1 and 3 digits. The \s specified whitespace.
The reorganization of names is a little convoluted, but when you use regexp with a cell input and tokens you get a cell of cells that needs some reformatting for your purposes.
I have a xpath expression which I want to use to extract City and date from a td which contains a string of this kind:
City(may contain spaces and may be missing, but the following space is always present) on 2013/07/20
So far, I got to the following solution for extracting the date, which works partially:
//path/to/my/td/text()/replace(.,'(.*) on (.*)','$3')
This works when City is present, but when City is missing I get "on 2013/07/20" as a result.
I think this is because the first capturing group fails and so the number of groups is different.
How can I get this expression to work?
I did not fully check your regex, but it looks fine at first sight. Anyway, you can also go an easier way if you only want to get the date by extracting the text after "on ":
//path/to/my/td/text()/substring-after(.,'on ')
edit: or you may go the substring-way and select the last 10 characters of the content:
//path/to/my/td/text()/substring(., string-length(.) - 9)