Data types

In addition to the npy_datetime and npy_timedelta typedefs for npy_int64, NumPy defines two additional structs that represent time unit metadata and an “exploded” view of a datetime.

typePyArray_DatetimeMetaData

Represents datetime unit metadata.

typedef struct {
    NPY_DATETIMEUNIT base;
    int num;
} PyArray_DatetimeMetaData;

NPY_DATETIMEUNITbase

The unit of the datetime.

intnum

A multiplier for the unit.

typenpy_datetimestruct

An “exploded” view of a datetime value

typedef struct {
    npy_int64 year;
    npy_int32 month, day, hour, min, sec, us, ps, as;
} npy_datetimestruct;

enumNPY_DATETIMEUNIT

Time units supported by NumPy. The “FR” in the names of the enum variants is short for frequency.

enumeratorNPY_FR_ERROR

Error or undetermined units.

enumeratorNPY_FR_Y

Years

enumeratorNPY_FR_M

Months

enumeratorNPY_FR_W

Weeks

enumeratorNPY_FR_D

Days

enumeratorNPY_FR_h

Hours

enumeratorNPY_FR_m

Minutes

enumeratorNPY_FR_s

Seconds

enumeratorNPY_FR_ms

Milliseconds

enumeratorNPY_FR_us

Microseconds

enumeratorNPY_FR_ns

Nanoseconds

enumeratorNPY_FR_ps

Picoseconds

enumeratorNPY_FR_fs

Femtoseconds

enumeratorNPY_FR_as

Attoseconds

enumeratorNPY_FR_GENERIC

Unbound units, can convert to anything

Conversion functions

intNpyDatetime_ConvertDatetimeStructToDatetime64(PyArray_DatetimeMetaData*meta, constnpy_datetimestruct*dts, npy_datetime*out)

Converts a datetime from a datetimestruct to a datetime in the units specified by the unit metadata. The date is assumed to be valid.

If the num member of the metadata struct is large, there may be integer overflow in this function.

Returns 0 on success and -1 on failure.

intNpyDatetime_ConvertDatetime64ToDatetimeStruct(PyArray_DatetimeMetaData*meta, npy_datetimedt, npy_datetimestruct*out)

Converts a datetime with units specified by the unit metadata to an exploded datetime struct.

Returns 0 on success and -1 on failure.

intNpyDatetime_ConvertPyDateTimeToDatetimeStruct(PyObject*obj, npy_datetimestruct*out, NPY_DATETIMEUNIT*out_bestunit, intapply_tzinfo)

Tests for and converts a Python datetime.datetime or datetime.date object into a NumPy npy_datetimestruct.

out_bestunit gives a suggested unit based on whether the object was a datetime.date or datetime.datetime object.

If apply_tzinfo is 1, this function uses the tzinfo to convert to UTC time, otherwise it returns the struct with the local time.

Returns -1 on error, 0 on success, and 1 (with no error set) if obj doesn’t have the needed date or datetime attributes.

intNpyDatetime_ParseISO8601Datetime(charconst*str, Py_ssize_tlen, NPY_DATETIMEUNITunit, NPY_CASTINGcasting, npy_datetimestruct*out, NPY_DATETIMEUNIT*out_bestunit, npy_bool*out_special)

Parses (almost) standard ISO 8601 date strings. The differences are:

• The date “20100312” is parsed as the year 20100312, not as equivalent to “2010-03-12”. The ‘-’ in the dates are not optional.
• Only seconds may have a decimal point, with up to 18 digits after it (maximum attoseconds precision).
• Either a ‘T’ as in ISO 8601 or a ‘ ‘ may be used to separate the date and the time. Both are treated equivalently.
• Doesn’t (yet) handle the “YYYY-DDD” or “YYYY-Www” formats.
• Doesn’t handle leap seconds (seconds value has 60 in these cases).
• Doesn’t handle 24:00:00 as synonym for midnight (00:00:00) tomorrow
• Accepts special values “NaT” (not a time), “Today”, (current day according to local time) and “Now” (current time in UTC).

str must be a NULL-terminated string, and len must be its length.

unit should contain -1 if the unit is unknown, or the unit which will be used if it is.

casting controls how the detected unit from the string is allowed to be cast to the ‘unit’ parameter.

out gets filled with the parsed date-time.

out_bestunit gives a suggested unit based on the amount of resolution provided in the string, or -1 for NaT.

out_special gets set to 1 if the parsed time was ‘today’, ‘now’, empty string, or ‘NaT’. For ‘today’, the unit recommended is ‘D’, for ‘now’, the unit recommended is ‘s’, and for ‘NaT’ the unit recommended is ‘Y’.

Returns 0 on success, -1 on failure.

intNpyDatetime_GetDatetimeISO8601StrLen(intlocal, NPY_DATETIMEUNITbase)

Returns the string length to use for converting datetime objects with the given local time and unit settings to strings. Use this when constructing strings to supply to NpyDatetime_MakeISO8601Datetime.

intNpyDatetime_MakeISO8601Datetime(npy_datetimestruct*dts, char*outstr, npy_intpoutlen, intlocal, intutc, NPY_DATETIMEUNITbase, inttzoffset, NPY_CASTINGcasting)

Converts an npy_datetimestruct to an (almost) ISO 8601 NULL-terminated string. If the string fits in the space exactly, it leaves out the NULL terminator and returns success.

The differences from ISO 8601 are the ‘NaT’ string, and the number of year digits is >= 4 instead of strictly 4.

If local is non-zero, it produces a string in local time with a +-#### timezone offset. If local is zero and utc is non-zero, produce a string ending with ‘Z’ to denote UTC. By default, no time zone information is attached.

base restricts the output to that unit. Set base to -1 to auto-detect a base after which all the values are zero.

tzoffset is used if local is enabled, and tzoffset is set to a value other than -1. This is a manual override for the local time zone to use, as an offset in minutes.

casting controls whether data loss is allowed by truncating the data to a coarser unit. This interacts with local, slightly, in order to form a date unit string as a local time, the casting must be unsafe.

Returns 0 on success, -1 on failure (for example if the output string was too short).