If you just want to play around (no commercial use) you can download kdb+ from here: https://kx.com/software-download.php but you only get the 32-bit version for free, so keep your DB under 4 GB. With kdb+ you get K, the language, Q, which is a superset of K, and a column (time-series) oriented database engine. I recommend against using it, because if you want to do something meaningful (like make money somehow) then you need to buy a commercial license. I hear that they cost around $2k per machine (or possibly per core).
Kona is nice but it is a full version behind K (Kona is a copy of K3, and kdb+ is on K4) and it isn't quite as fast/optimized. It's great if you are set on using K but don't have the cash and don't need database integration.
Kerf (by the same guy who made Kona) has a friendlier syntax but seems to be commercially oriented similar to K (as in email us for free demo software but pay up when you want to do it for real).
J is open source, free for commercial use, has some decent tutorials written for it, and even has a free database engine (JDB requires a license for commercial use, but Jd seems to be free for everything. It probably isn't as fast as K, but it has a nice feel to it. The runtime is under 3 MB and even with a Qt IDE and a bunch of extras it's under 30 MB. You can make Qt base GUIs with J and do quite a few things.
I started learning J just last week and have been doing some problems on Project Euler to get familiar with it. I like it quite a bit. It even has built in functions for prime factorization, finding the prime number sieve, and and extended precision mode which makes solving some problems very easy.
If you just want to play around (no commercial use) you can download kdb+ from here: https://kx.com/software-download.php but you only get the 32-bit version for free, so keep your DB under 4 GB. With kdb+ you get K, the language, Q, which is a superset of K, and a column (time-series) oriented database engine. I recommend against using it, because if you want to do something meaningful (like make money somehow) then you need to buy a commercial license. I hear that they cost around $2k per machine (or possibly per core).
Kona is nice but it is a full version behind K (Kona is a copy of K3, and kdb+ is on K4) and it isn't quite as fast/optimized. It's great if you are set on using K but don't have the cash and don't need database integration.
Kerf (by the same guy who made Kona) has a friendlier syntax but seems to be commercially oriented similar to K (as in email us for free demo software but pay up when you want to do it for real).
J is open source, free for commercial use, has some decent tutorials written for it, and even has a free database engine (JDB requires a license for commercial use, but Jd seems to be free for everything. It probably isn't as fast as K, but it has a nice feel to it. The runtime is under 3 MB and even with a Qt IDE and a bunch of extras it's under 30 MB. You can make Qt base GUIs with J and do quite a few things.
I started learning J just last week and have been doing some problems on Project Euler to get familiar with it. I like it quite a bit. It even has built in functions for prime factorization, finding the prime number sieve, and and extended precision mode which makes solving some problems very easy.