What is the use of variables in Robotframework setup?

Question

If possible explain me with an simple example for better understanding.

Answer 1

Use of variables is recommended in the following cases:

1. When strings change often in the test data. With variables you only need to make these changes in one place.
2. When creating system-independent and operating-system-independent test data. Using variables instead of hard-coded strings eases that considerably (for example, ${RESOURCES} instead of c:\resources, or ${HOST} instead of 10.0.0.1:8080). Because variables can be set from the command line when tests are started, changing system-specific variables is easy (for example, --variable HOST:10.0.0.2:1234 --variable RESOURCES:/opt/resources). This also facilitates localization testing, which often involves running the same tests with different strings.
3. When there is a need to have objects other than strings as arguments for keywords.
4. When different keywords, even in different test libraries, need to communicate. You can assign a return value from one keyword to a variable and give that as an argument to another.
5. When values in the test data are long or otherwise complicated. For example, ${URL} is shorter than http://tech.queryhome.com/