You need to specify that you mean PM instead of AM.

>>> from datetime import *
>>> m2 = '1:35 PM'
>>> m2 = datetime.strptime(m2, '%I:%M %p')
>>> print(m2)
1900-01-01 13:35:00

This approach uses strptime and strftime with format directives as per https://docs.python.org/2/library/datetime.html#strftime-strptime-behavior, %H is the 24 hour clock, %I is the 12 hour clock and when using the 12 hour clock, %p qualifies if it is AM or PM.

    >>> from datetime import datetime
    >>> m2 = '1:35 PM'
    >>> in_time = datetime.strptime(m2, "%I:%M %p")
    >>> out_time = datetime.strftime(in_time, "%H:%M")
    >>> print(out_time)
    13:35

time = raw_input().strip() # input format in hh:mm:ssAM/PM
t_splt = time.split(':')
if t_splt[2][2:] == 'PM' and t_splt[0] != '12':
    t_splt[0] = str(12+ int(t_splt[0]))
elif int(t_splt[0])==12 and t_splt[2][2:] == 'AM':
    t_splt[0] = '00'
t_splt[2] = t_splt[2][:2]
print ':'.join(t_splt)

Try this

dicti = 
{'01':13,'02':14,'03':15,'04':16,'05':17,'06':18,'07':19,'08':20,'09':21,'10':22,'11':23,'12':12}
s = '12:40:22PM'
if s.endswith('AM'):
if s.startswith('12'):
    s1=s[:8]
    bb=s1.replace('12','00')
    print bb
else:
    s1=s[:8]
    print s1
else:
s1=s[:8]
time= str(s[:2])
ora=str(dicti[time])
aa=s1.replace(time,ora)
print aa

If date is in this format (HH:MM:SSPM/AM) the following code is effective :

a=''
def timeConversion(s):
   if s[-2:] == "AM" :
      if s[:2] == '12':
          a = str('00' + s[2:8])
      else:
          a = s[:-2]
   else:
      if s[:2] == '12':
          a = s[:-2]
      else:
          a = str(int(s[:2]) + 12) + s[2:8]
   return a


s = '11:05:45AM'
result = timeConversion(s)
print(result)

%H Hour (24-hour clock) as a zero-padded decimal number.
%I Hour (12-hour clock) as a zero-padded decimal number.

m2 = "1:35" ## This is in the afternoon.
m2 = datetime.strptime(m2, "<b>%I</b>:%M")
print(m2)

One more way to do this cleanly

def format_to_24hr(twelve_hour_time):
return datetime.strftime(
datetime.strptime(
twelve_hour_time, '%Y-%m-%d %I:%M:%S %p'
), "%Y-%m-%d %H:%M:%S")

Instead of using “H” for hour indication use “I” as described in the example bellow:

from datetime import *
m2 = 'Dec 14 2018 1:07PM'
m2 = datetime.strptime(m2, '%b %d %Y %I:%M%p')
print(m2)

Please check this link

def timeConversion(s):
    if "PM" in s:
        s=s.replace("PM"," ")
        t= s.split(":")
        if t[0] != '12':
            t[0]=str(int(t[0])+12)
            s= (":").join(t)
        return s
    else:
        s = s.replace("AM"," ")
        t= s.split(":")
        if t[0] == '12':
            t[0]='00'
            s= (":").join(t)
        return s

To convert 12 hour time format into 24 hour time format

”’ To check whether time is ‘AM’ or ‘PM’ and whether it starts with
12 (noon or morning). In case time is after 12 noon then we add
12 to it, else we let it remain as such. In case time is 12
something in the morning, we convert 12 to (00) ”’

def timeConversion(s):

    if s[-2:] == 'PM' and s[:2] != '12':
        time = s.strip('PM')
        conv_time = str(int(time[:2])+12)+time[2:]

    elif s[-2:] == 'PM' and s[:2] == '12':
        conv_time = s.strip('PM')

    elif s[-2:] == 'AM' and s[:2] == '12':
        time = s.strip('AM')
        conv_time = '0'+str(int(time[:2])-12)+time[2:]

    else:
        conv_time = s.strip('AM')
        
    return conv_time

the most basic way is:

t_from_str_12h = datetime.datetime.strptime(s, "%I:%M:%S%p")
str_24h =  t_from_str.strftime("%H:%M:%S")

#format HH:MM PM
def convert_to_24_h(hour):
    if "AM" in hour:
        if "12" in hour[:2]:
            return "00" + hour[2:-2]
        return hour[:-2]
    elif "PM" in hour:
        if "12" in hour[:2]:
            return hour[:-2]
    return str(int(hour[:2]) + 12) + hour[2:5]

Since most of the manual calculation seems a bit complicated, I am sharing my way of doing it.

# Assumption: Time format (hh:mm am/pm) - You can add seconds as well if you need
def to_24hr(time_in_12hr):
    hr_min, am_pm = time_in_12hr.lower().split()
    hrs, mins = [int(i) for i in hr_min.split(":")]
    hrs %= 12
    hrs += 12 if am_pm == 'pm' else 0
    return f"{hrs}:{mins}"

print(to_24hr('12:00 AM'))

# 12-hour to 24-hour time format
import re

s = '12:05:45PM'


def timeConversion(s):
    hour = s.split(':')
    lastString = re.split('(d+)', hour[2])
    if len(hour[2]) > 2:
        hour[2] = lastString[1]
    if 'AM' not in hour or 'am' not in hour or int(hour[0]) < 12:
        if (lastString.__contains__('PM') and int(hour[0]) < 12) or (lastString.__contains__('pm') and int(hour[0]) < 12):
            hour[0] = str(int(hour[0]) + 12)
    if hour[0] == '12' and (lastString.__contains__('AM') or lastString.count('am')):
        hour[0] = '00'
    x = "{d}:{m}:{y}".format(d=hour[0], m=hour[1], y=hour[2])
    return x


print(timeConversion(s))

Here’s my solution by using python builtin functions to convert 12-hour time format into 24-hour time format

def time_conversion(s):
    if s.endswith('AM') and s.startswith('12'):
        s = s.replace('12', '00')
    if s.endswith('PM') and not s.startswith('12'):
        time_s = s.split(':')
        time_s[0] = str(int(time_s[0]) + 12)
        s = ":".join(time_s)
        
    s = s.replace('AM', '').replace('PM', '')
    
    return s
          

time_conversion('07:05:45PM') 

19:05:45