2011年4月27日 · Short answer: : return_valueUnless you use : (return) or ‘ (signal) to specify otherwise, a q function returns the value of its last expression. Since functions are lists of expressions separated by semicolons, both of the following functions return 3: q)single_expression: {3} q)single_expression[] 3 q)last_expression: {1; 2; 3} q)last_expression[] 3 q) To return a value other than that of ...

To achieve the equivalent of a void return in C, make the expression after the last semi-colon in the function body empty. q)fvoid:{[x] `a set x;} q)fvoid 42 q) In fact, the actual return value is the nil item :: that is a stand-in for void in this situation. Its display is suppressed in the q console but it can be revealed.

2018年6月29日 · Since + is overloaded to work with both atom and list , res:func[x;y] will work perfectly fine; however in cases when a dyadic function only accepts the arguments as atoms rather than lists then each-both will do the trick:. q)select res:func'[x;y] from tab // using each-both func'[x;y] res --- 5 7 9 e.g To select as many charecters as c from column s ...

2023年10月31日 · You can just return a list consisting of two elements, your modified list and the original list, or anything really. f:{[originalList] newList:modify[originalList]; :(originalList;newList); } basically you're returning a list of list, where the first list is …

2018年2月8日 · There is a function in kdb generating multiple tables as results. My main aim is to analyze each of the table generated using python. Is there a way I can make it return a list of table or some dictionary of tables so I can export it to python or should I try something else? Any leads on this is appreciated. Thanks

qSQL syntax. The select query returns a table for both call-by-name and call-by-value.. Since 4.1t 2021.03.30, select from partitioned tables maps relevant columns within each partition in parallel when running with secondary threads.. Minimal form¶. The minimal form of the query returns the evaluated table expression. q)tbl:([] id:1 1 2 2 2;val:100 200 300 400 500) q)select from tbl id val ...

Syntax of the q programming language. Tokens¶. All the ASCII symbols have syntactic significance in q. Some denote functions, that is, actions to be taken; some denote nouns, which are acted on by functions; some denote iterators, which modify nouns and functions to produce new functions; some are grouped to form names and constants; and others are punctuation that bound and separate ...

2011年3月13日 · select[n]. The first example below retrieves the first 10 rows, whereas the second example retrieves the last 10 rows: select [10] from table where date=2011.02.27 select [-10] from table where date=2011.02.27 If the table is in memory, you can use the virtual column i to retrieve a specific range of rows: If you want to retrieve specific rows by index from a partitioned table, use .Q.ind. C.f ...

Explicit return¶ To terminate evaluation successfully and return a value, use an empty assignment, which is : with a value to its right and no variable to its left. q)c:0 q)f:{a:6;b:7;:a*b;c::98} q)f 0 42 q)c 0. Evaluation control. Abort¶ To abort evaluation immediately, use Signal, which is ' with a value to its right.

2013年10月4日 · KDB - run a function where the function name and parameters are passed in as a string. 0. Pass multiple function parameter by column kdb q. 2. call function with multiple value kdb\q. 2. Parameterizing a kdb q script. 0. calling a function and its arguments from a table in q. 0.