q / KDB+ How to iterate through list of strings

Question

I have recently began learning q programming language and I find it a little bit of a struggle since I am coming from the 'traditional' imperative, OOP, etc language background. I am trying to perform a seemingly simple task - find strings in list that contain specific character:

names:("Saint Denis";"Rhodes";"Strawberry";"Valentine")

How do I print all strings that contain letter "R"? Even better, both "R" and "r"?

The furthest I was able to get is this:

{[x]x?"o"} each names

What would be the correct approach?

Thanks in advance!

Matthew Madill · Accepted Answer · 2021-06-17 16:23:58Z

7

You could use the like keyword with a regular expression like so:

q)names where names like "*[Rr]*"
"Rhodes"
"Strawberry"

answered Jun 17, 2021 at 16:23

Matthew Madill

8904 silver badges5 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Adam Bonham · Accepted Answer · 2021-06-17 15:45:11Z

3

You could use something like the below

q)names where "R" in/: names
"Rhodes"
q)names where any each "rR" in/: names
"Rhodes"
"Strawberry"

answered Jun 17, 2021 at 15:45

Adam Bonham

6154 silver badges7 bronze badges

Comments

Scott · Accepted Answer · 2021-06-17 16:48:51Z

3

Another couple of alternatives are:

q)names where "r" in'lower names
"Rhodes"
"Strawberry"

q)names where any"Rr"in'\:names
"Rhodes"
"Strawberry"

answered Jun 17, 2021 at 16:48

Scott

3341 silver badge9 bronze badges

Collectives™ on Stack Overflow

q / KDB+ How to iterate through list of strings

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related