Python compile() Function

Python compile() Function

The python compile() function takes source code as input and returns a code object which can later be executed by exec() function.

Signature

compile(source, filename, mode, flag, dont_inherit, optimize)

Parameters

• source - normal string, a byte string, or an AST (Abstract Syntax Trees) object.
• filename - File from which the code is read.
• mode - mode can be either exec or eval or single.
  • eval - if the source is a single expression.
  • exec - if the source is block of statements.
  • single - if the source is single statement.
• flags and dont_inherit - Default Value= 0. Both are optional parameters. It monitors that which future statements affect the compilation of the source.
• optimize (optional) - Default value -1. It defines the optimization level of the compiler.

Return

It returns a Python code object.

Let's see some examples of compile() function which are given below:

Python compile() Function Example 1

This example shows to compile a string source to the code object.

1. # compile string source to code  
2. code_str = 'x=5\ny=10\nprint("sum =",x+y)'  
3. code = compile(code_str, 'sum.py', 'exec')  
4. print(type(code))  
5. exec(code)  
6. exec(x)  

Output:

<class 'code'>
sum = 15

Python compile() Function Example 2

This example shows to read a code from the file and compile.

Let's say we have mycode.py file with following content.

1. x = 10  
2. y = 20  
3. print('Multiplication = ', x * y)  

We can read this file content as a string ,compile it to code object and execute it.

1. # reading code from a file  
2. f = open('my_code.py', 'r')  
3. code_str = f.read()  
4. f.close()  
5. code = compile(code_str, 'my_code.py', 'exec')  
6. exec(code)  

Output:

Multiplication =200