Question

Python

8.20 (Regular Expressions: Munging Dates) Dates are stored and displayed in several common formats. Three common formats are

042555

04/25/1955

April 25, 1955

Use regular expressions to search a string containing dates, find substrings that match these formats and munge them into other formats. The original string should have one date in each format, so there will be a total of six transformations.

This question is taken directly from the textbook.

Answer 1

CODE:

import re

months = ['January','February','March','April','May','June','July','August','September','October','November','December'] # list of months

txt = "date in format 1: 042555, date in format 2: 05/13/1956, date in format 3: August 18, 1954."

# text from which date is to be find and munged

print(txt)

format1 = re.search("[0-9][0-9][0-9][0-9][0-9][0-9]",txt) # finding 6 digits from text

if format1: # if date in format 1 is found

format1 = format1.group() # grouping the searched format

f1 = re.findall("[0-9][0-9]",format1) # making list of all 2 digit numbers

f1month = f1[0] # first item of list is month

f1date = f1[1] # second item of list is date

f1year = "19"+f1[2] # third item of list is year

format12 = f1month + "/" + f1date + "/" + f1year # munging into format 2

format13 = months[int(f1month)-1] + " " + f1date + ", " + f1year # munging into format 3

print(format1) # printing in format 1

print(format12) # printing in format 2

print(format13) # printing in format 3

print()

format2 = re.search("[0-9][0-9]/[0-9][0-9]/[0-9][0-9][0-9][0-9]",txt) # searching format 2

if format2: # if date in format 2 is found

format2 = format2.group() # grouping the searched format

f2 = re.findall("[0-9][0-9]",format2) # making list of all 2 digit numbers

f2month = f2[0] # first item of list is month

f2date = f2[1] # second item of list is date

f2year = f2[2]+f2[3] # third and fourth item of list is year

format21 = f2month + f2date + f2[3] # munging into format 1

format23 = months[int(f2month)-1] + " " + f2date + ", " + f2year # munging into format 3

print(format2)

print(format21)

print(format23)

print()

c=0

for month in months: # for all item in list months

c = c+1 # counting months

format3 = re.search(month + " [0-9][0-9], [0-9][0-9][0-9][0-9]",txt) # searching format 3

if format3: # if date in format 3 is found

format3 = format3.group() # grouping the searched format

if c<10: # if counter of month is less than 10

f3month = "0"+str(c) # 0 is added with converted integer

else:

f3month = str(c) # original counter converted to string

f3 = re.findall("[0-9][0-9]",format3) # making list of all 2 digit numbers

f3date = f3[0] # first item of list is date

f3year = f3[1]+f3[2] # second and third item of list is year

format31 = f3month + f3date + f3[2] # munging into format 1

format32 = f3month + "/" + f3date + "/" + f3year # munging into format 2

print(format3)

print(format31)

print(format32)

break # to break out of loop

SAMPLE OUTPUT: