def strptime(data_string, format="%a %b %d %H:%M:%S %Y"):
    """Return a time struct based on the input string and the format string."""
    global _TimeRE_cache
    _cache_lock.acquire()
    try:
        time_re = _TimeRE_cache
        locale_time = time_re.locale_time
        if _getlang() != locale_time.lang:
            _TimeRE_cache = TimeRE()
        if len(_regex_cache) > _CACHE_MAX_SIZE:
            _regex_cache.clear()
        format_regex = _regex_cache.get(format)
        if not format_regex:
            format_regex = time_re.compile(format)
            _regex_cache[format] = format_regex
    finally:
        _cache_lock.release()
    found = format_regex.match(data_string)
    if not found:
        raise ValueError("time data did not match format:  data=%s  fmt=%s" %
                         (data_string, format))
    if len(data_string) != found.end():
        raise ValueError("unconverted data remains: %s" %
                          data_string[found.end():])
    year = 1900
    month = day = 1
    hour = minute = second = 0
    tz = -1
    # weekday and julian defaulted to -1 so as to signal need to calculate values
    weekday = julian = -1
    found_dict = found.groupdict()
    for group_key in found_dict.keys():
        if group_key == 'y':
            year = int(found_dict['y'])
            # Open Group specification for strptime() states that a %y
            #value in the range of [00, 68] is in the century 2000, while
            #[69,99] is in the century 1900
            if year <= 68:
                year += 2000
            else:
                year += 1900
        elif group_key == 'Y':
            year = int(found_dict['Y'])
        elif group_key == 'm':
            month = int(found_dict['m'])
        elif group_key == 'B':
            month = locale_time.f_month.index(found_dict['B'].lower())
        elif group_key == 'b':
            month = locale_time.a_month.index(found_dict['b'].lower())
        elif group_key == 'd':
            day = int(found_dict['d'])
        elif group_key == 'H':
            hour = int(found_dict['H'])
        elif group_key == 'I':
            hour = int(found_dict['I'])
            ampm = found_dict.get('p', '').lower()
            # If there was no AM/PM indicator, we'll treat this like AM
            if ampm in ('', locale_time.am_pm[0]):
                # We're in AM so the hour is correct unless we're
                # looking at 12 midnight.
                # 12 midnight == 12 AM == hour 0
                if hour == 12:
                    hour = 0
            elif ampm == locale_time.am_pm[1]:
                # We're in PM so we need to add 12 to the hour unless
                # we're looking at 12 noon.
                # 12 noon == 12 PM == hour 12
                if hour != 12:
                    hour += 12
        elif group_key == 'M':
            minute = int(found_dict['M'])
        elif group_key == 'S':
            second = int(found_dict['S'])
        elif group_key == 'A':
            weekday = locale_time.f_weekday.index(found_dict['A'].lower())
        elif group_key == 'a':
            weekday = locale_time.a_weekday.index(found_dict['a'].lower())
        elif group_key == 'w':
            weekday = int(found_dict['w'])
            if weekday == 0:
                weekday = 6
            else:
                weekday -= 1
        elif group_key == 'j':
            julian = int(found_dict['j'])
        elif group_key == 'Z':
            # Since -1 is default value only need to worry about setting tz if
            # it can be something other than -1.
            found_zone = found_dict['Z'].lower()
            for value, tz_values in enumerate(locale_time.timezone):
                if found_zone in tz_values:
                    # Deal with bad locale setup where timezone names are the
                    # same and yet time.daylight is true; too ambiguous to
                    # be able to tell what timezone has daylight savings
                    if time.tzname[0] == time.tzname[1] and \
                       time.daylight:
                            break
                    else:
                        tz = value
                        break
    # Cannot pre-calculate datetime_date() since can change in Julian
    #calculation and thus could have different value for the day of the week
    #calculation
    if datetime_date:
        if julian == -1:
            # Need to add 1 to result since first day of the year is 1, not 0.
            julian = datetime_date(year, month, day).toordinal() - \
                      datetime_date(year, 1, 1).toordinal() + 1
        else:  # Assume that if they bothered to include Julian day it will
               #be accurate
            datetime_result = datetime_date.fromordinal((julian - 1) + datetime_date(year, 1, 1).toordinal())
            year = datetime_result.year
            month = datetime_result.month
            day = datetime_result.day
        if weekday == -1:
            weekday = datetime_date(year, month, day).weekday()
    return (year, month, day, hour, minute, second, weekday, julian, tz)
Return a time struct based on the input string and the format string.
recipes/Python/56036_Pure_Python_strptime/recipe-56036.py