Reorder table columns

x xcols y    xcols[x;y]

Where

• y is a simple table, passed by value
• x is a symbol vector of some or all of y’s column names

returns y with x as its first column/s.

q)\l trade.q
q)cols trade
`time`sym`price`size
q)trade:xcols[reverse cols trade;trade] / reverse cols and reassign trade
q)cols trade
`size`price`sym`time
q)trade:`sym xcols trade                / move sym to the front
q)cols trade
`sym`size`price`time