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How to JSON serialize sets?
...ecoder
import pickle
class PythonObjectEncoder(JSONEncoder):
def default(self, obj):
if isinstance(obj, (list, dict, str, unicode, int, float, bool, type(None))):
return JSONEncoder.default(self, obj)
return {'_python_object': pickle.dumps(obj)}
def as_python_object...
Undo git update-index --skip-worktree
...
Aha! I simply want:
git update-index --no-skip-worktree <file>
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How can I remove 3 characters at the end of a string in php?
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<?php echo substr("abcabcabc", 0, -3); ?>
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The cast to value type 'Int32' failed because the materialized value is null
...handling, where there can be unexpected nulls in different places. ...DefaultIfEmpty(0).Sum(0) can help in this (quite simple) case, where there might be no elements and sql's SUM returns null whereas c# expect 0.
A more general approach is to use ?? which will be translated to COALESCE whenever th...
How do you delete an ActiveRecord object?
...r.destroy(15)
User.where(age: 20).destroy_all
User.destroy_all(age: 20)
Alternatively you can use delete and delete_all which won't enforce :before_destroy and :after_destroy callbacks or any dependent association options.
User.delete_all(condition: 'value') will allow you to delete records
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Iterating each character in a string using Python
... if you really wanna force a square peg into a round hole.
i = 0
while i < len(str):
print str[i]
i += 1
But then again, why do that when strings are inherently iterable?
for i in str:
print i
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Await on a completed task same as task.Result?
...but just to chime in...
There are two reasons why I prefer await over Result (or Wait). The first is that the error handling is different; await does not wrap the exception in an AggregateException. Ideally, asynchronous code should never have to deal with AggregateException at all, unless it speci...
Python creating a dictionary of lists
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You can use defaultdict:
>>> from collections import defaultdict
>>> d = defaultdict(list)
>>> a = ['1', '2']
>>> for i in a:
... for j in range(int(i), int(i) + 2):
... d[j].append(i)
...
>>&g...
How to use gitignore command in git
...ete files that should be ignored, or untrack them with
# git rm --cached <file list or pattern>
# stage all the changes git commit
git add -A
from now on your repository will not have them tracked.
If you would like to clean up your history, you can
# if you want to correct the last 10 ...
Django in / not in query
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table1.objects.exclude(id__in=
table2.objects.filter(your_condition).values_list('id', flat=True))
The exclude function works like the Not operator you where asking for. The attribute flat = True tells to table2 query to return the value_list as a one level list. So... a...