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Retain cycle on `self` with blocks
...sue is identical to the workaround for the retain issue; namely, using the __block storage class for the variable.
In any case, to answer your question, there's no real alternative here. If you're designing your own block-based API, and it makes sense to do so, you could have the block get passed t...
How to add pandas data to an existing csv file?
...ws=1, sep=sep).columns).all():
raise Exception("Columns and column order of dataframe and csv file do not match!!")
else:
df.to_csv(csvFilePath, mode='a', index=False, sep=sep, header=False)
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...
Python argparse: Make at least one argument required
...
args = vars(parser.parse_args())
if not any(args.values()):
parser.error('No arguments provided.')
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improve this answer
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...
Python division
...t:
>>> float(10 - 20) / (100 - 10)
-0.1111111111111111
or from __future__ import division, which the forces / to adopt Python 3.x's behavior that always returns a float.
>>> from __future__ import division
>>> (10 - 20) / (100 - 10)
-0.1111111111111111
...
How can I mock requests and the response?
...mock
# This is the class we want to test
class MyGreatClass:
def fetch_json(self, url):
response = requests.get(url)
return response.json()
# This method will be used by the mock to replace requests.get
def mocked_requests_get(*args, **kwargs):
class MockResponse:
d...
How to iterate through two lists in parallel?
... And to zip until both iterators are
exhausted, you would use
itertools.zip_longest.
Python 2
In Python 2, zip
returns a list of tuples. This is fine when foo and bar are not massive. If they are both massive then forming zip(foo,bar) is an unnecessarily massive
temporary variable, and should be r...
How to get a reversed list view on a list in Java?
...
Unlike Collections.reverse, this is purely a view... it doesn't alter the ordering of elements in the original list. Additionally, with an original list that is modifiable, changes to both the original list and the view are reflected in the other.
...
Change a Django form field to a hidden field
...get the value.
also you may prefer to use in the view:
form.fields['field_name'].widget = forms.HiddenInput()
but I'm not sure it will protect save method on post.
Hope it helps.
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improv...
What is the fastest way to check if a class has a function defined?
...tr() to get the attribute, and callable() to verify it is a method:
invert_op = getattr(self, "invert_op", None)
if callable(invert_op):
invert_op(self.path.parent_op)
Note that getattr() normally throws exception when the attribute doesn't exist. However, if you specify a default value (None...
How do I import other TypeScript files?
...ler as follows:
tsc --module amd app.ts
This then gets compiled to
var __extends = this.__extends || function (d, b) {
function __() { this.constructor = d; }
__.prototype = b.prototype;
d.prototype = new __();
}
define(["require", "exports", 'moo'], function(require, exports, __moo_...