Language - (Variable | Field) in Python.
A variable name must start with a letter and must exclude certain special symbols such as the dot (period). The underscore is allowed in a variable name.
mynum = 4 + 1
The variable being assigned to is called the left-hand side of an assignment, and the expression whose value is assigned is called the right-hand side.
A variable can be bound to a value of any type. You can rebind mynum to a string:
>>> mynum = 'Brown'
An assignment statement binds a variable to the value of an expression, not to the expression itself. Python fi rst evaluates the right-hand side and only then assigns the resulting value to the left-hand side.
The binding lasts until you assign some other value to the variable or until you end your Python session. It is called a top-level binding.
Name resolution of free variables occurs at runtime, not at compile time. This means that the following code will print 42:
i = 10
def f():
print(i)
i = 42
f()
expression if condition else expression
>>> x=1
>>> x if x<0 else -x
-1
>>> x if x>0 else -x
1
Initialization and extraction of variables via Python - (Un)Packing
| Function | Description |
|---|---|
| dir() | list of variables in scope |
| globals() | a dictionary of global variables |
| locals() | a dictionary of local variables |
del variableName