forked from shibing624/python-tutorial
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy path08.compile.py
More file actions
55 lines (44 loc) · 1.1 KB
/
08.compile.py
File metadata and controls
55 lines (44 loc) · 1.1 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
# -*- coding: utf-8 -*-
"""
@description: 动态编译
@author:XuMing
"""
from __future__ import print_function # 兼容python3的print写法
from __future__ import unicode_literals # 兼容python3的编码处理
# Byte Code 编译
# Python, Java 等语言先将代码编译为 byte code（不是机器码），然后再处理：
# .py -> .pyc -> interpreter
# eval(statement, glob, local)
# 使用 eval 函数动态执行代码，返回执行的值：
a = 1
b = eval('a+2')
print(b)
# exec(statement, glob, local)
# 使用 exec 可以添加修改原有的变量:
a = 1
exec ('b = a + 10')
print(b)
local = dict(a=2)
glob = {}
exec ("b = a+1", glob, local)
print(local)
# compile 函数生成 byte code
# compile(str, filename, mode)
a = 1
b = compile('a+2', '', 'eval')
print(eval(b))
a = 1
c = compile("b=a+4", "", 'exec')
exec (c)
print(b)
# abstract syntax trees
import ast
tree = ast.parse('a+10', '', 'eval')
ast.dump(tree)
a = 1
c = compile(tree, '', 'eval')
d = eval(c)
print(d)
# 安全的使用方法 literal_eval ，只支持基本值的操作：
b = ast.literal_eval('[10.0, 2, True, "foo"]')
print(b)