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kdb .Q dot Q Functions
kdb provides the following functions/variables within the .Q namespace:
Contents
Common .Q Functions
| Function | Details |
|---|---|
| .Q.f | Formats a number similar to the printf command with a .%.2f argument. |
| .Q.fmt | Formats a number to a fixed number of characters and dp. |
| .Q.s | Format an object to plain text (used by the q console, obeys \\c setting |
| .Q.addr | ip-address as an integer from a hostname symbol |
| .Q.host | hostname as a symbol for an integer ip-address |
| .Q.fc | parallel on cut |
| .Q.fs | Loops over file (in chunks) applying function |
| .Q.gc | Invokes the garbage collector. |
Disk Storage .Q Functions
| Function | Details |
|---|---|
| .Q.cn | number of rows for partitioned table passed by value |
| .Q.pn | Partition counts cached since the last time .Q.cn was called |
| .Q.dpft | .Q.dpft[directory;partition;`p#field;tablename] |
| Saves a table splayed to a specific partition of a database sorted (`p#) on a specified field | |
| .Q.en | .Q.en[`:db; table] |
| Enumerates any character columns in a table to sym and appends any new entries to a file in the db directory. | |
| .Q.hdpf | .Q.hdpf[historicalport;directory;partition;`p#field] save all tables and notify host |
Missing or Empty Tables - .Q Functions
| Function | Details |
|---|---|
| .Q.chk | fills missing tables |
| .Q.vp | dictionary detailing which tables have missing partitions |
| .Q.bv | function that can be called to build the dictionary |
Partitioned Tables - .Q Functions
| Function | Details |
|---|---|
| .Q.qt | Returns 1b if x is a table, 0b otherwise. |
| .Q.qp | Returns 1b if given a partitioned table, 0b if splayed table, else 0 |
| .Q.ind | it takes a partitioned table and (long!) indices into the table |
| .Q.PV | In partitioned dbs, contains a list of partition values - conformant to date |
| .Q.pv | .Q.PV as modified by .Q.view. |
| .Q.view | set a subview eg .Q.view 2#date |