Question

我正在尝试从列表中导入模块。这将允许更容易编辑导入的模块，更清晰的错误消息和更好的错误处理。这基本上就是我想做的事情：

imports = ['sys', 'itertools', 'datetime', 'os']
for x in imports:
    try:
        import x
        print "Successfully imported ", x, '.'
    except ImportError:
        print "Error importing ", x, '.'

这里的问题是它尝试导入x，而不是x应该保持的值。我意识到要从列表导入我可以做类似下面的事情，但我没有看到用它来处理错误的方法：

imports = ['sys', 'itertools', 'datetime', 'os']
modules = map(__import__, imports)

有没有办法将错误处理与此方法集成，还是应该尝试不同的方法？

Answer 1

而不是将它们全部映射到___import__，只需将每个模块一次附加到for循环内的列表modules中：

imports = ['sys', 'itertools', 'datetime', 'os']
modules = []
for x in imports:
    try:
        modules.append(__import__(x))
        print "Successfully imported ", x, '.'
    except ImportError:
        print "Error importing ", x, '.'

但请注意，大多数Python程序员更喜欢使用importlib.import_module而不是__import__来执行此任务。

另请注意，使modules字典而不是列表更好：

imports = ['sys', 'itertools', 'datetime', 'os']
modules = {}
for x in imports:
    try:
        modules[x] = __import__(x)
        print "Successfully imported ", x, '.'
    except ImportError:
        print "Error importing ", x, '.'

现在，而不是索引：

modules[0].version
modules[3].path

您可以按名称访问模块：

modules["sys"].version
modules["os"].path

Answer 2

这在Python 3.7上对我有用

modules = ["sys","os","platform","random","time","functools"]

for library in modules:
try:
    exec("import {module}".format(module=library))
except Exception as e:
    print(e)
print(sys.argv)

导入子模块：

modules = ["PyQt5"] # pip install PyQt5
submodules = ["QtCore"]

for library in modules:
    for sublibrary in submodules:
        try:
            exec("from {m} import {s}".format(m=library, s=sublibrary))
        except Exception as e:
            print(e)
print(dir()) # Includes QtCore
print(dir(QtCore)) # All functions, classes and variables are exactly correct as with "from PyQt5 import QtCore"

导入所有内容：

modules = ["sys","os","platform","random","time","functools"]
for library in modules:
    try:
        exec("from {module} import *".format(module=library))
    except Exception as e:
        print(e)
print(dir()) # Exactly working as thought

导入实例或其他内容

modules = ["PyQt5"] # pip install PyQt5
submodules = ["QtCore"]
func = ["QCoreApplication"]
for library in modules:
    for f in func:
        for sublibrary in submodules:
            try:
                exec("from {m}.{s} import {f}".format(m=library, s=sublibrary, f=f)) 
            except Exception as e:
                print(e)
print(dir()) # Includes QCoreApplication instance

从模块的子模块导入所有内容：

modules = ["PyQt5"] # pip install PyQt5
submodules = ["QtCore"]
for library in modules:
    for sublibrary in submodules:
        try:
            exec("from {m}.{s} import *".format(m=library, s=sublibrary)) # Didn't mention f"" strings all the times. But for beginners .format is better.
        except Exception as e:
            print(e)
print(dir()) # Includes all PyQt5.QtCore stuff

Answer 3

您可以修改import x行以使用__import__(x)格式

imports = ['sys', 'itertools', 'datetime', 'os','doesntexit']
for x in imports:
    try:
        __import__(x)
        print "Success"
    except ImportError:
        print "Error ", x

输出：

Success
Success
Success
Success
Error  doesntexit

Answer 4

您可以通过编程方式导入，并使用import x as y与globals具有相同的作用：

packages_to_import = [{'name': 'numpy'
                       'as': 'np'}]

for package in packages:
    package_name = package['name']
    import_as = package.get('as', package_name)

    globals()[import_as] = __import__(package_name)

print(np.version.full_version)

Answer 5

没有一个投票最多的选项对我有用。它们似乎已成功导入，但是以后无法使用。万一您遇到相同的问题，this tutorial会为我解决。

modules = ['sys', 'itertools', 'datetime', 'os']  

for lib in modules:
    globals()[lib] = __import__(lib)

PS：我猜他们之前没有被添加到我的全局变量中

从Python中的列表导入模块

5 个答案: