I am still a KDB noob. This page will be kept updating whenever I have new tricks.
Open a file where file name is in variable
filePath:"/tmp/test.txt"
file:hopen hsym[`$filePath]
Delete a file
hdel `:/home/franz/test.txt
Check if a file exists
not () ~ key hsym `:/home/franz/test.txt
Delete a file only if it exists
if[not () ~ key hsym `:/home/franz/test.txt; hdel `:/home/franz/test.txt]
Define a table
table1:([] c1:1 2; c2:`abc`def; c3:123 456)
Define a single row table
table1:([] enlist c1:1; c2:`abc; c3:123)
Write a single string to file (Not append)
`:/home/franz/test.txt 0: "Hello world"
Export a table to csv
File name is same as the table name.
save `$"/home/franz/table1.csv"
Export a table to csv with a different file name
`:/home/franz/test.txt 0: csv 0: table1
Load csv file to table
"jsj" is the data type of each column in the csv. For example, j is long and s is symbol.
table3:("jsj";enlist",")0:`$"/home/franz/table1.csv"
try-catch
h:@[hopen;`::9999;{show "Unable to connect"; exit 1}]
Early return
Use : without anything on the left
:"Hello World"
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