How to remove [] in Json format data?

[vikram1583]

I have a field properties.policies  in json format 

field value: [{"fieldname":"fieldvalue","fieldname":"fieldvalue","fieldname":"fieldvalue",[priview] "fieldname":"fieldvalue",[]}]

i want to remove first and last [] so that other fields can populate 

can some one send me the rex please ?

Thanks in advance

[ITWhisperer]

| eval field=trim(field,"[]")

[richgalloway]

What have you tried so far? 

Parsing JSON using regular expressions can be challenging.  Have you tried the spath command?