月和日的缩写

Question

我正在尝试编写regex来捕获

的输出

datetime.datetime.now().ctime()

Mon May 25 20:20:41 2015

我想知道什么是星期和月的缩写可能的输出?

Answer 1

以下是ctime生成的字符串格式的一些信息。基本上，它总是一个固定长度的字符串，具有基本格式

Answer 2

Python datetime类不调用C ctime()函数，即，即使在不提供C ctime()(相当于asctime(localtime(clock)))的平台上，它也可以工作。

CPython源代码说格式是:

static PyObject *
format_ctime(PyDateTime_Date *date, int hours, int minutes, int seconds)
{
    static const char *DayNames[] = {
        "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"
    };
    static const char *MonthNames[] = {
        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
    };
    int wday = weekday(GET_YEAR(date), GET_MONTH(date), GET_DAY(date));
    return PyUnicode_FromFormat("%s %s %2d %02d:%02d:%02d %04d",
                                DayNames[wday], MonthNames[GET_MONTH(date)-1],
                                GET_DAY(date), hours, minutes, seconds,
                                GET_YEAR(date));
}

您可以使用C语言环境中的datetime.strptime(input_ctime_string, "%a %b %d %H:%M:%S %Y")来解析它。

以上(几乎)与相应的asctime()定义相同:

char *asctime(const struct tm *timeptr)
{
    static char wday_name[7][3] = {
        "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
    };
    static char mon_name[12][3] = {
        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
    };
    static char result[26];

    sprintf(result, "%.3s %.3s%3d %.2d:%.2d:%.2d %dn",
        wday_name[timeptr->tm_wday],
        mon_name[timeptr->tm_mon],
        timeptr->tm_mday, timeptr->tm_hour,
        timeptr->tm_min, timeptr->tm_sec,
        1900 + timeptr->tm_year);
    return result;
}