我想enumerate在迭代器上使用类似函数来生成该对(previous_element, current_element).也就是说,由于iter是
i0, i1, i1, ...
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我想offset(iter)屈服
(None, i0), (i0, i1), (i1, i2) ...
Run Code Online (Sandbox Code Playgroud) 我正在尝试安装mlpy,但我收到以下错误.我不知道从哪里开始.有人有任何线索吗?
$ sudo easy_install mlpy-3.5.0.tar.gz
Password:
install_dir /Library/Frameworks/Python.framework/Versions/6.2/lib/python2.6/site-packages/
Processing mlpy-3.5.0.tar.gz
Running mlpy-3.5.0/setup.py -q bdist_egg --dist-dir /tmp/easy_install-lQNT_3/mlpy-3.5.0/egg-dist-tmp-EPgtAi
mlpy/gsl/gsl.c:223:24: error: gsl/gsl_sf.h: No such file or directory
mlpy/gsl/gsl.c:224:39: error: gsl/gsl_statistics_double.h: No such file or directory
error: Setup script exited with error: command 'gcc' failed with exit status 1
Run Code Online (Sandbox Code Playgroud) 下面的代码应创建一个Counter模型并使用(延迟)任务将计数器增加到10.访问时'/'应该创建一个单独的Counter对象count = 10.这在生产中发生.在开发(localhost)Counter中,创建了多个对象,其中最大的对象为10:

我怀疑这是因为put开发时不同步(但似乎总是在生产中).有没有办法让它们同步?
以下代码段:
class Counter(ndb.Model):
count = ndb.IntegerProperty(indexed=False)
def reset():
ndb.delete_multi(Counter().query().fetch(keys_only=True, use_cache=False, use_memcache=False))
def increment():
counter = Counter().query().get(use_cache=False, use_memcache=False)
if not counter:
counter = Counter(count=0)
counter.count += 1
counter.put()
if counter.count < 10:
deferred.defer(increment)
@app.route('/')
def hello():
"""Return a friendly HTTP greeting."""
reset()
deferred.defer(increment)
return 'Hello World!'
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python google-app-engine app-engine-ndb google-cloud-datastore