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How do I execute inserts and updates in an Alembic upgrade script?
... other forms.
Note that Alembic provides some basic data functions: op.bulk_insert() and op.execute(). If the operations are fairly minimal, use those. If the migration requires relationships or other complex interactions, I prefer to use the full power of models and sessions as described below.
T...
How do I get indices of N maximum values in a NumPy array?
...t;> a = [1, 3, 2, 4, 5]
>>> heapq.nlargest(3, range(len(a)), a.__getitem__)
[4, 3, 1]
If you use Python 2, use xrange instead of range.
Source: heapq — Heap queue algorithm
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Print current call stack from a method in Python code
...port traceback
def f():
g()
def g():
for line in traceback.format_stack():
print(line.strip())
f()
# Prints:
# File "so-stack.py", line 10, in <module>
# f()
# File "so-stack.py", line 4, in f
# g()
# File "so-stack.py", line 7, in g
# for line in traceback.form...
Best way to select random rows PostgreSQL
...ery:
SELECT count(*) AS ct -- optional
, min(id) AS min_id
, max(id) AS max_id
, max(id) - min(id) AS id_span
FROM big;
The only possibly expensive part is the count(*) (for huge tables). Given above specifications, you don't need it. An estimate will do just fine,...
How to convert CFStringRef to NSString?
...e using ARC, the new casting syntax is as follows:
NSString *aNSString = (__bridge NSString *)aCFString;
works as well. The key thing to note is that CoreFoundation will often return objects with +1 reference counts, meaning that they need to be released (all CF[Type]Create format functions do th...
Converting string from snake_case to CamelCase in Ruby
... you're using Rails, String#camelize is what you're looking for.
"active_record".camelize # => "ActiveRecord"
"active_record".camelize(:lower) # => "activeRecord"
If you want to get an actual class, you should use String#constantize on top of that.
"app_user".came...
In Python, how can you load YAML mappings as OrderedDicts?
...rary code this is a bad idea. Also, it doesn't directly work with yaml.safe_load().
Fortunately, the solution can be improved without much effort:
import yaml
from collections import OrderedDict
def ordered_load(stream, Loader=yaml.Loader, object_pairs_hook=OrderedDict):
class OrderedLoader(L...
Google maps API V3 - multiple markers on exact same spot
...nt.
google.maps.event.trigger(markerClusterer, 'clusterclick', this.cluster_);
var zoom = this.map_.getZoom();
var maxZoom = markerClusterer.getMaxZoom();
// if we have reached the maxZoom and there is more than 1 marker in this cluster
// use our onClick method to popup a list of options
if (zoom ...
What is the difference between AF_INET and PF_INET in socket programming?
What is the difference between AF_INET and PF_INET in socket programming?
7 Answers
7
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python exception message capturing
...is no longer supported in python 3. Use the following instead.
try:
do_something()
except BaseException as e:
logger.error('Failed to do something: ' + str(e))
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