A variable is a memory location where a programmer can store a value. The value stored in a variable can be accessed or updated later. The interpreter allocates memory on the basis of data type of a variable.
Variables names must start with a letter or an underscore, such as:
The remainder of your variable name may consist of letters, numbers and underscores.
Names are case sensitive.
case_sensitive, CASE_SENSITIVE, and Case_Sensitive are each a different variable.
Good Variable Name
Choose meaningful name instead of short name. roll_no is better than rn.
Maintain the length of a variable name. Roll_no_of_a-student is too long?
Be consistent; roll_no or or RollNo
Begin a variable name with underscore(_) character for special case.