The QTypes class defines mapping between the q and corresponding C# types.
| qSharp type identifier | q num type | q type | C# type |
|------------------------|---------------|-----------------------|---------------|
| Bool | -1 | boolean | bool |
| BoolList | 1 | boolean list | bool[] |
| Byte | -4 | byte | byte |
| ByteList | 4 | byte list | byte[] |
| Guid | -2 | guid | System.Guid |
| GuidList | 2 | guid list | System.Guid[] |
| Short | -5 | short | short |
| ShortList | 5 | short list | short[] |
| Int | -6 | integer | int |
| IntList | 6 | integer list | int[] |
| Long | -7 | long | long |
| LongList | 7 | long list | long[] |
| Float | -8 | real | float |
| FloatList | 8 | real list | float[] |
| Double | -9 | float | double |
| DoubleList | 9 | float list | double[] |
| Char | -10 | character | char |
| String | 10 | string | char[] |
| Symbol | -11 | symbol | string |
| SymbolList | 11 | symbol list | string[] |
| Timestamp | -12 | timestamp | QTimestamp |
| TimestampList | 12 | timestamp list | QTimestamp[] |
| Month | -13 | month | QMonth |
| MonthList | 13 | month list | QMonth[] |
| Date | -14 | date | QDate |
| DateList | 14 | date list | QDate[] |
| Datetime | -15 | datetime | QDateTime |
| DatetimeList | 15 | datetime list | QDateTime[] |
| Timespan | -16 | timespan | QTimespan |
| TimespanList | 16 | timespan list | QTimespan[] |
| Minute | -17 | minute | QMinute |
| MinuteList | 17 | minute list | QMinute[] |
| Second | -18 | second | QSecond |
| SecondList | 18 | second list | QSecond[] |
| Time | -19 | time | QTime |
| TimeList | 19 | time list | QTime[] |
| GeneralList | 0 | general list | object[] |
| Lambda | 100, 104 | function body | QLambda |
| Table | 98 | table | QTable |
| KeyedTable | 99 | keyed table | QKeyedTable |
| Dictionary | 99 | dictionary | QDictionary |
q language provides multiple types for operating on temporal data. The qSharp library provides a corresponding temporal class for each q temporal type.
Instance of each class can be created:
- from from the underlying base type (
longin case ofQTimespanandQTimestamp,doublein case ofQDateTime, etc.), - via conversion from System.DateTime instance,
- from q String representation via factory method
fromString(...)
Every temporal class in the qSharp library implements the IDateTime interface:
public object GetValue() // Returns internal q representation of the temporal data
public DateTime ToDateTime() // Represents a q date/time with the instance of System.DateTimeThe QTypes utility class exposes a static method GetQNull(QType type) that returns corresponding q null value of given type. Keep in mind that null values are only defined and available for primitive q types.
As null values in q are represented as arbitrary values, it is also possible to produce null value without explicitly calling the GetQNull method. q null values are mapped to C# according to the following table:
| kdb+ type | C# null |
|---------- | --------------------------------|
| bool | false |
| byte | (byte) 0 |
| guid | new UUID(0, 0) |
| short | short.MinValue |
| int | int.MinValue |
| long | long.MinValue |
| real | float.NaN |
| double | double.NaN |
| character | ' ' |
| symbol | "" |
| timestamp | new QTimestamp(long.MinValue) |
| month | new QMonth(int.MinValue) |
| date | new QDate(int.MinValue) |
| datetime | new QDateTime(double.NaN) |
| timespan | new QTimespan(long.MinValue) |
| minute | new QMinute(int.MinValue) |
| second | new QSecond(int.MinValue) |
| time | new QTime(int.MinValue) |