[rocuinneagain]

Something more like:

q)750{(x[0]+1;x[1]+x[2];x[2])}/0

0 2 750 1500 2

Or use a dictionary for readability:

q)750{x[`ID]+:1;x[`y]:sum x`y`z;x}/`ID`y`z!0 0 2

ID| 750

y | 1500

z | 2

 

[rocuinneagain]

Are you on Windows/Linux/Mac?

1. Esc works in Windows (PowerShell + CMD)
2. In Linux (Bash) Ctrl +E, Ctrl + U https://stackoverflow.com/a/16687377/4256419

On Linux/Mac rlwrap is suggested.

 

 

[rocuinneagain]

Instructions now also added for adding inline code to your questions & messages.

[rocuinneagain]

https://code.kx.com/q4m3/6_Functions/#677-more-over-iteration

The final overload of / is equivalent to a while loop in imperative programming. It provides a declarative way to specify a test to end the iteration. Thinking functionally, we provide a predicate function that is applied to the result at each step. The iteration continues as long as the predicate result is 1b and stops otherwise. For example, we stop the computation of the Fibonacci sequence once it exceeds 1000 as follows.

q)fib:{x,sum -2#x} q)fib/[{1000>last x}; 1 1] 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597

 

Your code accidentally boiled down to an infinite loop as the result never moves to 0b

1 1/[sums;1]

 

/Each iteration it runs 1 1[1] / Which returns 1 /Then sums 1 /This returns 1 /This is a non zero value which gets treated as 1b so the loop starts again /Infinite loop

[rocuinneagain]

Using parse helps to see what is happening.

 

Parsing a simplified version of your query helped to show the order of execution in the parse tree:

q)-1 .Q.s1 last value last parse "select sums(size)/sum(size) from tab"; ((/;`size);+;(sum;`size))

The q equivalent can then be shown to have the same parse tree

q)-1 .Q.s1 parse"size/[sums;sum size]"; ((/;`size);+;(sum;`size))

 

 

[rocuinneagain]

https://code.kx.com/platform/deployment/lin_prerequisites/#host-configuration

Kdb+ licenses (k4.lic) are tied to the hostname of a machine and specifically the hostname in FQDN (<HOSTNAME>.<DOMAINNAME>) format. 

The installer expects the hostname to be the the required FQDN format .i.e server1.company.com

[rocuinneagain]

q){k:key y;x upsert enlist (k where k in cols x)#y}[x;td2] 
a b c 
------- 
1 I 10 
2 J 20 
3 K 30 
99 a

[rocuinneagain]

This is likely close to how qsql  would be used based on your example

 

//Read CSV and store in memory table 
myCSV:("PFFFFF";enlist csv) 0: `$":/q/spy.csv" 
//Only retain lines where Line and close do not equal 0 
myCSV:select from myCSV where Line<>0, close<>0 
//Add deltas other extra columns 
myCSV:update dc:deltas Line, dclose:deltas close, dc2:1+til count i, dclose2:1+til count i from myCSV 
//Display the table myCSV

 

If you run those lines in Developer then you can use myCSVin your Dashboard widget to display it as the data is stored in an in memory table.

set stores data in kdb+ binary files (not human readable).

If you wish to save as CSV either of these should work for you:

`:myCSV.csv 0: csv 0: myCSV save `myCSV.csv

 

[rocuinneagain]

You can so this using over

q)tab:([] A:1 2 3;B:4 5 6;C:7 8 9) 
// Sample table 
q)tab 
A B C 
----- 
1 4 7 
2 5 8 
3 6 9 
q)func:{![x;();0b;enlist[y]!enlist (+;y;1)]} 
//Function I want to run 
q)func[tab;`A] // Same as: update A:A+1 from tab 
A B C 
----- 
2 4 7 
3 5 8 
4 6 9 
q)func over enlist[tab],`A`B`C // Using over accumulator 
A B C 
------ 
2 5 8 
3 6 9 
4 7 10

 

 

 

[rocuinneagain]

It is a projection on take

q)1#1b ,1b 
q)2#1b 11b 
q)#[;1b] 1 ,1b 
q)#[;1b] 2 11b

 

 

[rocuinneagain]

Another Github user recently created a new Go interface: jshinonome/geek: golang interface for kdb+/q (github.com)

[rocuinneagain]

This behaviour happens with file handles also:

Applying the handle to data appends it to the file as bytes.
Applying the neg of the handle to char data appends it as text. The result of a successful operation is the positive or negative handle.

File system | Basics | kdb+ and q documentation – Kdb+ and q documentation (kx.com)

As to why I am not sure. The choice could have been made to return a generic null (::) instead possibly.

 

For stdout and stderr it can feel strange at first but it is not printing ‘hello1’ in one go. Instead ‘hello’ is printed as you requested then as you are in an interactive session the q) prompt wants to display the returned object so it then prints ‘1’.

q)1"hello"; //The ; stops the q) prompt from printing the returned object '1' hello
q)
q)-1"hello"; //-1 is often more useful as it includes a n newline char hello

 

[rocuinneagain]

1. How are you trying to plot the data? table, bar, line etc. ?
2. Are you seeing an error? Why do you say it cannot be plotted?

 

Common components to chart:

• Data Grid – KX Dashboards
• Canvas Chart – KX Dashboards

[rocuinneagain]

This is batching mode when the timer t is set. https://code.kx.com/q/basics/syscmds/#t-timer

In this mode the TP will cache data and only publish it when the timer triggers .z.ts https://code.kx.com/q/ref/dotz/#zts-timer

In this case t is a list of tables and it calls pub on each of them (' form)  https://code.kx.com/q/ref/maps/#each

value is called so that the cached data from the TP is populated in pub to send to subscribers (RDB etc.)

Some more information on batch mode: https://code.kx.com/q/wp/tick-profiling/

 

q)upd'[t;value each t] 
//A demo 'upd' which prints the parameters sent to it 
q)a:([] c1:1 2 3) 
q)b:([] c2:4 5 6) 
q)t:tables[] //Create list of tables 
q)t `s#`a`b 
q)upd'[t;value each t] (`a;+(,`c1)!,1 2 3) (`b;+(,`c2)!,4 5 6)

 

 

[rocuinneagain]

Can you include a small reproducible piece of code?

I do not see the files being created.

//Including kdb+ version information 
//If behaviour has changed include previous version information also 
q).z.k 2021.07.12 
q).z.K 4f 
//An example table
q)ot:([]a:1 2 3;b:`a`b`n;c:("jj";"kk";"pp")) 
q)save `ot `:ot 
//No # or ## files created by `save` keyword 
q){x where x like "ot*"}key `:. ,`ot

 

The # and ## files you see are used by the anymap datatype on disk.

You can still read your file with

get `:ot