Python syntax eval function

Python syntax: eval function

usage

eval(expression, globals=None, locals=None)

parameter:

• expression: a required parameter, which can be a string or any code object instance (which can be created by the compile function). If it is a string, it will be analyzed and interpreted as a Python expression.
• globals: Optional parameter, representing the global namespace (storing global variables). If provided, it must be a dictionary object.
• locals: Optional parameter, representing the current local namespace (storing local variables), if provided, any mapping object can be used. If omitted, it will take the same value as globals.
• If both globals and locals are ignored, they will take the global namespace and local namespace under the environment where the eval() function is called.

example

1. Simple expression

print(eval('1+2'))

Output result: 3

2. String to dictionary

print(eval("{'name':'linux','age':18}")

Output result: {'name':'linux','age':18}

3. Pass global variables

print(eval("{'name':'linux','age':age}"{
    
    "age":500}))

Output result: {'name':'linux','age':1822}

4. Transfer local variables (local variables)

age = 20
print(eval("{'name':'linux','age':age}"{
    
    "age":500},locals()))

Output result: {'name':'linux','age':20}