Find and replace logic in Python

Question

In python I need a logic for below scenario I am using split function to this. I have string which contains input as show below.

"ID674021384 25/01/1986 heloo hi thanks 5 minutes and 25-01-1988."

"ID909900000 25-01-1986 hello 10 minutes."

And output should be as shown below which replace date format to "date" and time format to "time".

"ID674021384 date hello hi thanks time date."

"ID909900000 date hello time."

And also I need a count of date and time for each Id as show below

ID674021384 DATE:2 TIME:1

ID909900000 DATE:1 TIME:1

Use a properly defined regular expression to handle your input. It would help if you can show what code you have, otherwise give some more sample content. — cfedermann
– cfedermann, Commented Apr 13, 2012 at 13:37
this is a new requirement getting data from chat.. I am yet to start coding.. it looks like this Input chat "ID674021384 25/01/1986 Thank you You should be connected to an agent in approximately 0 minutes" And the out put should be "ID674021384 date Thank you You should be connected to an agent in approximately time" ID674021384 date:1 time :1 — vinod reddy
– vinod reddy, Commented Apr 13, 2012 at 14:19

jamylak · Accepted Answer · 2012-04-13 14:48:45Z

2

>>> import re
>>> from collections import defaultdict
>>> lines = ["ID674021384 25/01/1986 heloo hi thanks 5 minutes and 25-01-1988.", "ID909900000 25-01-1986 hello 10 minutes."]
>>> pattern = '(?P<date>\d{1,2}[/-]\d{1,2}[/-]\d{4})|(?P<time>\d+ minutes)'
>>> num_occurences = {line:defaultdict(int) for line in lines}
>>> def repl(matchobj):
        num_occurences[matchobj.string][matchobj.lastgroup] += 1
        return matchobj.lastgroup

>>> for line in lines:
        text_id = line.split(' ')[0]
        new_text = re.sub(pattern,repl,line)    
        print new_text
        print '{0} DATE:{1[date]} Time:{1[time]}'.format(text_id, num_occurences[line])
        print ''


ID674021384 date heloo hi thanks time and date.
ID674021384 DATE:2 Time:1

ID909900000 date hello time.
ID909900000 DATE:1 Time:1

answered Apr 13, 2012 at 14:48

jamylak

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2 Comments

vinod reddy Over a year ago

Thank you jamylak.. Can you please share me the python tutorials where we can develop our skills in python. I want to learn python. this is my Id: [email protected]

jamylak Over a year ago

No problem. Not sure about which tutorials as there are many different resources you can look up depending on your skills. This question has been asked before on this site so you can look it up.

QuantumOmega · Accepted Answer · 2012-04-13 13:44:03Z

1

For parsing similar lines of text, like log files, I often use regular expressions using the re module. Though split() would work well also for separating fields which don't contain spaces and the parts of the date, using regular expressions allows you to also make sure the format matches what you expect, and if need be warn you of a weird looking input line.

Using regular expressions, you could get the individual fields of the date and time and construct date or datetime objects from them (both from the datetime module). Once you have those objects, you can compare them to other similar objects and write new entries, formatting the dates as you like. I would recommend parsing the whole input file (assuming you're reading a file) and writing a whole new output file instead of trying to alter it in place.

As for keeping track of the date and time counts, when your input isn't too large, using a dictionary is normally the easiest way to do it. When you encounter a line with a certain ID, find the entry corresponding to this ID in your dictionary or add a new one to it if not. This entry could itself be a dictionary using dates and times as keys and whose values is the count of each encountered.

I hope this answer will guide you on the way to a solution even though it contains no code.

answered Apr 13, 2012 at 13:44

QuantumOmega

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3 Comments

jamylak Over a year ago

Unless the question is tagged as homework, code is usually expected as an answer...

Li-aung Yip Over a year ago

@jamylak: A code-free answer is an acceptable response to a code and research-free question.

Li-aung Yip Over a year ago

I'm upvoting because QuantumOmega recommended the use of the datetime module to parse dates and times, instead of trying to do it in regex. (Quick! Write me a regex that recognises arbitrary dates and times! )

ccbunney · Accepted Answer · 2012-04-13 14:41:33Z

You could use a couple of regular expressions:

import re

txt = 'ID674021384 25/01/1986 heloo hi thanks 5 minutes and 25-01-1988.'

retime = re.compile('([0-9]+) *minutes')
redate = re.compile('([0-9]+[/-][0-9]+[/-][0-9]{4})')

# find all dates in 'txt'
dates = redate.findall(txt)
print dates

# find all times in 'txt'
times = retime.findall(txt)
print times

# replace dates and times in orignal string:
newtxt = txt
for adate in dates:
    newtxt = newtxt.replace(adate, 'date')

for atime in times:
    newtxt = newtxt.replace(atime, 'time')

The output looks like this:

Original string:
ID674021384 25/01/1986 heloo hi thanks 5 minutes and 25-01-1988.
Found dates:['25/01/1986', '25-01-1988']
Found times: ['5']

New string:
ID674021384 date heloo hi thanks time minutes and date.

Dates and times found:
ID674021384 DATE:2 TIME:1

Chris

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