PySnooper 可以打印出 Python 执行代码的全流程和每行代码的执行时间，以及执行过程中变量的变化。
安装 PySnooper
$ pip install pysnooper
简单示例
import pysnooper
@pysnooper.snoop()
def text(number):
new_list = []
for i in range(number):
new_list.append(i * 2)
return new_list
text(6)
效果
Source path:... text.py
Starting var:.. number = 6
10:45:31.237191 call 5 def text(number):
10:45:31.237644 line 6 new_list = []
New var:....... new_list = []
10:45:31.237732 line 7 for i in range(number):
New var:....... i = 0
10:45:31.237849 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0]
10:45:31.237941 line 7 for i in range(number):
Modified var:.. i = 1
10:45:31.238024 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0, 2]
10:45:31.238088 line 7 for i in range(number):
Modified var:.. i = 2
10:45:31.238157 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0, 2, 4]
10:45:31.238229 line 7 for i in range(number):
Modified var:.. i = 3
10:45:31.238303 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0, 2, 4, 6]
10:45:31.238364 line 7 for i in range(number):
Modified var:.. i = 4
10:45:31.238432 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0, 2, 4, 6, 8]
10:45:31.238500 line 7 for i in range(number):
Modified var:.. i = 5
10:45:31.238570 line 8 new_list.append(i * 2)
Modified var:.. new_list = [0, 2, 4, 6, 8, 10]
10:45:31.238640 line 7 for i in range(number):
10:45:31.238713 line 9 return new_list
10:45:31.238767 return 9 return new_list
Return value:.. [0, 2, 4, 6, 8, 10]
可以很明显看到每次循环的操作和变量的变化。
其他操作
-
把输出内容写入文件
@pysnooper.snoop('/my/log/file.log')
-
显示函数调用的其他函数的执行过程
@pysnooper.snoop(depth=2)
示例
import pysnooper
class Text():
@pysnooper.snoop(depth=2)
def a(self, param):
return self.b(param)
def b(self, param):
new_list = []
for i in range(param):
new_list.append(i * 2)
Text().a(2)
-
给输出的行加前缀
@pysnooper.snoop(prefix='aaa ')
示例
import pysnooper
class Text():
@pysnooper.snoop(prefix='aaa ')
@pysnooper.snoop(depth=2)
def a(self, param):
return self.b(param)
def b(self, param):
new_list = []
for i in range(param):
new_list.append(i * 2)
Text().a(2)
结果
：这里的
pysnooper.snoop 顺序对结果有影响。
aaa Source path:... /Users/machao/Documents/PythonVirtual/SpeedyCloud/lib/python2.7/site-packages/pysnooper/tracer.py
aaa Starting var:.. args = (<__main__.Text instance at 0x101da2bd8>, 2)
aaa Starting var:.. kwargs = {}
aaa Starting var:.. function = <function a at 0x101da96e0>
aaa Starting var:.. self = <pysnooper.tracer.Tracer instance at 0x101da2b48>
aaa 11:15:53.951363 call 254 def simple_wrapper(*args, **kwargs):
aaa 11:15:53.954333 line 255 with self:
aaa 11:15:53.954468 line 256 return function(*args, **kwargs)
Source path:... /Users/machao/Desktop/licens.py
Starting var:.. self = <__main__.Text instance at 0x101da2bd8>
Starting var:.. param = 2
11:15:53.954581 call 6 def a(self, param):
11:15:53.954993 line 7 return self.b(param)
Starting var:.. self = <__main__.Text instance at 0x101da2bd8>
Starting var:.. param = 2
11:15:53.955131 call 9 def b(self, param):
11:15:53.955316 line 10 new_list = []
New var:....... new_list = []
11:15:53.955506 line 11 for i in range(param):
New var:....... i = 0
11:15:53.955675 line 12 new_list.append(i * 2)
Modified var:.. new_list = [0]
11:15:53.955818 line 11 for i in range(param):
Modified var:.. i = 1
11:15:53.956045 line 12 new_list.append(i * 2)
Modified var:.. new_list = [0, 2]
11:15:53.956168 line 11 for i in range(param):
11:15:53.956281 return 11 for i in range(param):
Return value:.. None
11:15:53.956454 return 7 return self.b(param)
Return value:.. None
aaa Call ended by exception
-
在执行线程的函数时打印内容
@pysnooper.snoop(thread_info=True)
-
控制最长输出
@pysnooper.snoop(max_variable_length=200)
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