How to make a INPUT as part of source code?

I would like to know how to use a input as a part of source code

for example, the source code looks like below

        data[80]='a'
        ...

        ...
        t=input("blabla")
        if(t):
            dosomething()

then when we input a string like

data[80]=='a'

then the dosomething() occurs.

How can I make this happen?