Using the Function Editor to replace special characters

Question

I am attempting to use the new Function Editor within QGIS 2.8.2. I have a field called LAND_NAME with hundreds of rows. What I'm trying to do is find and replace all "special characters". In ArcGIS, I would use this function:

codeblock:

def findreplace(s):
s = s.replace('(',   '').replace(')','').replace('&','and').replace('\'','~').replace('.','').replace(' ','_').replace('@','at').replace(',','').replace('/','_').replace('[','').replace(']','').replace(':','_')   
return s

In the function editor, I have gotten this far and am now stuck:

@qgsfunction(args='auto', group='Custom')
def findreplace(s):
s = replace("field",'(','')
return s

Any insights into how to replace all the special characters in the first codeblock and make a function in QGIS?

Answer 1

Like this:

@qgsfunction(args='auto', group='Custom')
def findreplace(s, feature, value):
   chars = [('(',  '')
        ,(')', '')
        ,('&', 'and')
        ,('\'', '~')
        ,('.', '')
        ,(' ', '_')
        ,('@', 'at')
        ,(', ', '')
        ,('/', '_')
        ,('[', '')
        ,(']', '')
        ,(':', '_')]

    for char, replacewith in chars:
        s = s.replace(char, replacewith)

   return s

call it like this:

findreplace("LAND_NAME")