Function days_to_month_number

numpy/core/src/multiarray/datetime.c:226–246

Extracts the month number from a 'datetime64[D]' value */

/* Extracts the month number from a 'datetime64[D]' value */
NPY_NO_EXPORT int
days_to_month_number(npy_datetime days)
{
    npy_int64 year;
    int *month_lengths, i;

    year = days_to_yearsdays(&days);
    month_lengths = _days_per_month_table[is_leapyear(year)];

    for (i = 0; i < 12; ++i) {
        if (days < month_lengths[i]) {
            return i + 1;
        }
        else {
            days -= month_lengths[i];
        }
    }

    /* Should never get here */
    return 1;
}

/*
 * Fills in the year, month, day in 'dts' based on the days