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Diffstat (limited to 'kdb+.html.markdown')
| -rw-r--r-- | kdb+.html.markdown | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/kdb+.html.markdown b/kdb+.html.markdown index 099d1529..5ae86a4f 100644 --- a/kdb+.html.markdown +++ b/kdb+.html.markdown @@ -6,7 +6,7 @@ contributors: filename: learnkdb.q --- -The q langauge and its database component kdb+ were developed by Arthur Whitney +The q language and its database component kdb+ were developed by Arthur Whitney and released by Kx systems in 2003. q is a descendant of APL and as such is very terse and a little strange looking for anyone from a "C heritage" language background. Its expressiveness and vector oriented nature make it well suited @@ -301,7 +301,7 @@ l:1+til 9 / til is a useful shortcut for generating ranges -5#l / => 5 6 7 8 9 / drop the last 5 -5_l / => 1 2 3 4 -/ find the first occurance of 4 +/ find the first occurrence of 4 l?4 / => 3 l[3] / => 4 @@ -316,7 +316,7 @@ key d / => `a`b`c / and value the second value d / => 1 2 3 -/ Indexing is indentical to lists +/ Indexing is identical to lists / with the first list as a key instead of the position d[`a] / => 1 d[`b] / => 2 @@ -406,7 +406,7 @@ k!t / We can also use this shortcut for defining keyed tables kt:([id:1 2 3]c1:1 2 3;c2:4 5 6;c3:7 8 9) -/ Records can then be retreived based on this key +/ Records can then be retrieved based on this key kt[1] / => c1| 1 / => c2| 4 @@ -428,7 +428,7 @@ kt[`id!1] f:{x+x} f[2] / => 4 -/ Functions can be annonymous and called at point of definition +/ Functions can be anonymous and called at point of definition {x+x}[2] / => 4 / By default the last expression is returned @@ -440,7 +440,7 @@ f[2] / => 4 / Function arguments can be specified explicitly (separated by ;) {[arg1;arg2] arg1+arg2}[1;2] / => 3 -/ or if ommited will default to x, y and z +/ or if omitted will default to x, y and z {x+y+z}[1;2;3] / => 6 / Built in functions are no different, and can be called the same way (with []) @@ -472,7 +472,7 @@ a / => 1 / Functions cannot see nested scopes (only local and global) {local:1;{:local}[]}[] / throws error as local is not defined in inner function -/ A function can have one or more of it's arguments fixed (projection) +/ A function can have one or more of its arguments fixed (projection) f:+[4] f[4] / => 8 f[5] / => 9 @@ -483,7 +483,7 @@ f[6] / => 10 ////////// q-sql ////////// //////////////////////////////////// -/ q has it's own syntax for manipulating tables, similar to standard SQL +/ q has its own syntax for manipulating tables, similar to standard SQL / This contains the usual suspects of select, insert, update etc. / and some new functionality not typically available / q-sql has two significant differences (other than syntax) to normal SQL: @@ -682,7 +682,7 @@ aj[`time`sym;trades;quotes] / where possible functionality should be vectorized (i.e. operations on lists) / adverbs supplement this, modifying the behaviour of functions / and providing loop type functionality when required -/ (in q functions are sometimes refered to as verbs, hence adverbs) +/ (in q functions are sometimes referred to as verbs, hence adverbs) / the "each" adverb modifies a function to treat a list as individual variables first each (1 2 3;4 5 6;7 8 9) / => 1 4 7 @@ -762,7 +762,7 @@ select from splayed / (the columns are read from disk on request) / kdb+ is typically used for data capture and analysis. / This involves using an architecture with multiple processes / working together. kdb+ frameworks are available to streamline the setup -/ and configuration of this architecuture and add additional functionality +/ and configuration of this architecture and add additional functionality / such as disaster recovery, logging, access, load balancing etc. / https://github.com/AquaQAnalytics/TorQ ``` |