• Symbol Column Update

    Question: Define a function updSymCol that takes in a table as a value or reference, column name, function to operate on the column that returns an updated column list, and enumeration domain (symbol, filepath) that the column is enumerated against. If a table reference is passed in, the update should be persisted and the reference should be returned, otherwise the updated value is returned.

    Example

                                    
                                q)show t:([]s:`AAPL`IBM`MSFT;p:100 200 300)
s    p
--------
AAPL 100
IBM  200
MSFT 300
q)`sym set `$()
`sym
q)updSymCol[t;`s;lower;`sym]
s    p
--------
aapl 100
ibm  200
msft 300
q)sym
`aapl`ibm`msft
q)updSymCol[`t;`s;upper;`sym]
`t
q)t
s    p
--------
AAPL 100
IBM  200
MSFT 300
q)sym
`aapl`ibm`msft`AAPL`IBM`MSFT
q)`:t/ set .Q.en[`:.] t
q)updSymCol[`:t/;`s;{`$1 rotate' string x};`:sym]
`:t/
q)updSymCol[`:t/;`s;{`$1 rotate' string x};`:sym]
`:t/
q)get `:t
s    p
--------
PLAA 100
MIB  200
FTMS 300
q)get `:sym
`AAPL`IBM`MSFT`APLA`BMI`SFTM`PLAA`MIB`FTMS

    Solution

    Tags:
    tables
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