I have a variable containing a string and in run time i was to replace some variables which are stored in that string.

for example..

```
 my_string = "Congrats you have joined groupName."
 groupName = "*Name of my group*"
  puts my_string

```

Output:-

```
 "Congrats you have joined *name of the group*"

```

issue is: 

```
my_string = " Congrats you have joined #{groupName}" expects groupName already exists.. but in my case i have to define my_string before variable in it.

```

Solution 1:

One way can be.. string replacment like using gsub.. but thats not good one..

PS:

What I am trying to achieve. We have some set of 100 messages that we have to deliver. I want to define at one single place and just replace some variable when needed. Now i want to define all these variables(100 ones) in the application\_controller, so that I can just concatenate each variable(one of 100) defined. And automatically variable(variable which is defined in the string stored in one of those 100 variables).
 *This language is quite confusing.. Check the example i explained above..*