Clarification needed in making dynamic selector

Hi All

When we pass variable in selector there are two ways we can pass.
aaname = ’"+variablename+"’
aaname = ‘{{variablename}}’

What is the difference between these two formats?

aaname = ’"+variablename+"’

This would be used if the variable is just a part of the selector, for example:
aaname = “Customer " + variablename + " page”

aaname = ‘{{variablename}}’

This you would use if variablename contains all the needed information/text

Thank you so much for your reply.

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