How to format a full year date/time

t = DateTime.now
crsdate = DateTime.strptime("23JAN","%d%b")
crsdate >= t ? crsdate >>= 12 : crsdate

locale | format pattern for skeleton “MMMMdjmm” | example
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
en_US    "MMMM d  'at'  h:mm a"                   April 2 at 5:00 PM
es_ES    "d 'de' MMMM, H:mm"                      2 de abril, 17:00
ja_JP    "M月d日 H:mm"                              4月2日 17:00

import pandas as pd
import re
from datetime import datetime 

def helper(a ,f):
    return datetime.strptime(a,f).strftime('%m-%d-%Y')

def change_format(a):
    #print a
    if 'Janaury' in a:
        a = a[:3]+a[7:]
    if 'Decemeber' in a:
        a = a[:3]+a[9:]
    c = re.split('/|-| ',a)
    b = len(c)
    if re.match(r'\d\d [A-Z]',a) != None:
        if len(c[1]) == 3:
            return helper(a,'%d %b %Y')
        else:
            return helper(a, '%d %B %Y')
    elif re.match(r'[A-Z]',a) != None:
        if len(c) == 2:
            if len(c[0]) == 3: 
                return helper(a+' 1','%b %Y %d')
            else:
                return helper(a+' 1','%B %Y %d')
        if len(c[0]) == 3:
            if ',' in a:
                return helper(a,'%b %d, %Y')
            else:
                return  helper(a,'%b %d %Y')
        else:
            if ',' in a:
                return helper(a,'%B %d, %Y')
            else:
                return helper(a,'%B %d %Y')
    else:
        if b==3:
            if len(c[2]) == 2:
                if '-' in a:
                    return helper(a,'%m-%d-%y')
                else:
                    return helper(a ,'%m/%d/%y')
            elif len(c[2]) == 4:
                return date(int(c[2]),int(c[0]),int(c[1])).strftime('%m-%d-%Y')
        elif b==2:
            return date(int(c[1]),int(c[0]),1).strftime('%m-%d-%Y')
        else:
            return date(int(c[0]),1,1).strftime('%m-%d-%Y')

with open('dates.txt') as f:
    d = f.read()
    f.close()
k = re.findall(r'\b(\d{1,2}\/\d{1,2}\/\d{2,4}|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]*-\d{2}-\d{2,4}|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{2}. )\d{4}|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{2}, )\d{4}|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{2} )\d{4}|(?:\d{2} )(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{4})|(?:\d{2} )(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z.]* (?:\d{4})|(?:\d{2} )(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z,]* (?:\d{4})|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{1,2})[a-z,]* (?:\d{4})|(?:Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)[a-z]* (?:\d{4})|\d{1,2}\/\d{4}|\d{4}|\d{1,2}-\d{1,2}-\d{2,4})\b',d)   
k.remove('7787')
dates =map(change_format,k)
dates.remove(None)
df = pd.DataFrame(dates,columns= ['date'])
df['date'] =pd.to_datetime(df.date)
df = df.sort_values('date').reset_index(drop=True)

df['date'] = pd.to_datetime(df['date']).dt.to_period('M')