Removing a Given Key from a Groovy Map

Question

I'm sure this is a very simple question, but I'm very new to Groovy and it's something I've been struggling with for awhile now. I have an HttpServletRequest and I need to do something with it's parameters. However, I want to exclude exactly 1 parameter.

Previously, I was using

req.getParameterMap

However, to remove the one value, I'm trying something along the lines of

def reqParams = req.getParameterMap?.remove('blah');

I know that the above does not quite work, but that's the psuedo-code for what I'm trying to achieve. I really need the new Map and the original req.getParameterMap() Objects to look exactly the same except for the one missing key. What's the best way to achieve this? Thanks!

Answer 1

req.getParameterMap returns an immutable map which cannot be modified. You need to create a new map, putAll from the parameter map and remove the required key you do not want.

def reqParams = [:] << req.getParameterMap()
reqParams.remove('blah')

You have your new map as reqParams (without the undesired key value pair) and the original parameter map.

Answer 2

You can use findAll function, somethig like:

def map = req.getParameterMap().findAll {it.key != 'blah'}