replace variable with its value in a ruby string, string itself is stored in a variable? -

i have variable containing string , in run time replace variables stored in string.

for example..

 my_string = "congrats have joined groupname."  groupname = "*name of group*"   puts my_string 

output:-

 "congrats have joined *name of group*" 

issue is:

my_string = " congrats have joined #{groupname}" expects groupname exists.. in case have define my_string before variable in it. 

solution 1:

one way can be.. string replacment using gsub.. thats not one..

ps:

what trying achieve. have set of 100 messages have deliver. want define @ 1 single place , replace variable when needed. want define these variables(100 ones) in application_controller, can concatenate each variable(one of 100) defined. , automatically variable(variable defined in string stored in 1 of 100 variables). this language quite confusing.. check example explained above..

you store format string:

my_string = "congrats have joined %s" group_name = "my group" puts my_string % group_name # prints: congrats have joined group 

for multiple variables in same string can use

my_string = "congrats have joined %s %s" group_name = ['group1', 'group2'] puts my_string % ['group1', 'group2']   

will result:--

"congrats have joined group1 group2"