Using Substitution on Text Field - Appian Expression Editor

Question

I am currently trying to figure out how to use the Substitute() function provided by Appian on a text field. Specifically, I am trying to substitute the "&" with & amp; because the ampersand is causing me issues when I try to save the form with a certain value. 
 Every combination that I've tried has given me an error that will either prevent me from saving my changes, or causes an error when I try to use the form it's related to. Has anyone used the Expression Editor in Appian before and knows how to use the substitution function with the code below? 
 We are currently using an older version of Appian (version 7.10). 
 Also - there is currently no tag available for Appian so I am unable to tag it properly :( 
 If there is any additional information I can provide to get this solved, please let me know.

sanghapriyab · Answer

Below code worked for me, please remember the saveInto function is invoked once you make a change in the text field. 
 
load( 
 local!value:"some text &", 
a!textField( 
 value:local!value, 
 saveInto:a!save(local!value,substitute(local!value,"&","_")) 
))

Carlos Santander · Answer

Check other answers to see how substitute() works, but if you want a more robust solution for replacing characters that can cause problems, check out the toHtml() function.