导入Python库并优化处理，如果它们不可用 [英] Importing Python libraries and gracefully handling if they are not availalble

问题描述

如果我只有一个try catch块，我会得到1个异常（第一个）。有没有一种模式来迭代所有的libs，并且每个单独缺少的lib都有一个单独的异常？

 ＃！/ usr / bin / env python 
 
 try：import sys 
除了：print sys.exc_info（）
 try：import numpy as np 
 except：print sys.exc_info ）
尝试：导入scipy作为sp 
除了：print sys.exc_info（）
 try：import os as os 
除了：print sys.exc_info（）
 try ：从运算符import itemgetter 
除了：print sys.exc_info（）
 try：import socket 
除了：print sys.exc_info（）
 try：import logging 
 except ：print sys.exc_info（）
 try：from time import gmtime，strftime 
 except：print sys.exc_info（）
  

解决方案

您可以使用 __ import __ 动态导入模块，允许您 - 除其他外 - 通过以名称迭代列表导入模块。

例如：

  libnames = ['numpy'，'scipy' 'operator'] 
在libnames中的libname：
 try：
 lib = __import __（libname）
除了：
打印sys.exc_info（）
其他：
 globals（）[libname] = lib 
  

您可以扩展它来处理导入...作为... 和从...导入... 表单或只是稍后进行分配手动，即：

  np = numpy 
 sp = scipy 
 itemgetter = operator.itemgetter 
  

I would like to import bunch of libraries and catch the exception.

If I have only 1 try catch block I get 1 exception (the first one). Is there a pattern to iterate over all of the libs and have a separate exception for each individual missing lib?

#!/usr/bin/env python

try: import sys
except: print sys.exc_info()
try: import numpy as np
except: print sys.exc_info()
try: import scipy as sp
except: print sys.exc_info()
try: import os as os
except: print sys.exc_info()
try: from operator import itemgetter
except: print sys.exc_info()
try: import socket
except: print sys.exc_info()
try: import logging
except: print sys.exc_info()
try: from time import gmtime, strftime
except: print sys.exc_info()

解决方案

You can use __import__ to dynamically import modules, allowing you to - among other things - import modules by iterating a list with their names.

For example:

libnames = ['numpy', 'scipy', 'operator']
for libname in libnames:
    try:
        lib = __import__(libname)
    except:
        print sys.exc_info()
    else:
        globals()[libname] = lib

You can either extend that to handle the import ... as ... and from ... import ... forms or just do the assignments later manually, ie.:

np = numpy
sp = scipy
itemgetter = operator.itemgetter

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