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How to avoid 'cannot read property of undefined' errors?
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Catching all exceptions without re-throwing is bad, and generally using exceptions as part of the expected flow of execution is also not great -- even though in this case it's pretty well contained.
– hugo
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PHP: How to send HTTP response code?
...-Code: 404', true, 404);
I recommend the 2nd one. The first does work on all browsers I have tested, but some minor browsers or web crawlers may have a problem with a header line that only contains a colon. The header field name in the 2nd. variant is of course not standardized in any way and coul...
In Django, how do I check if a user is in a certain group?
...add(group) # user is now in the "Editor" group
then user.groups.all() returns [<Group: Editor>].
Alternatively, and more directly, you can check if a a user is in a group by:
if django_user.groups.filter(name = groupname).exists():
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Note that groupname can also be the ac...
Determine if code is running as part of a unit test
I have a unit test (nUnit). Many layers down the call stack a method will fail if it is running via a unit test.
19 Answers...
How to print the ld(linker) search path
...he spot. I have a linking problem, during linking process linker finds manually installed libraries in /usr/local/.. which causes missing library error, and linking fails. I have to rename /usr/local everytime to exclude that search path. Is there a simple way to exclude or override /usr/local path?...
How do I include a pipe | in my linux find -exec command?
...ld result in only a single agrep process being spawned which would process all the output produced by numerous invocations of zcat.
If you for some reason would like to invoke agrep multiple times, you can do:
find . -name 'file_*' -follow -type f \
-printf "zcat %p | agrep -dEOE 'grep'\n" | s...
Trimming a huge (3.5 GB) csv file to read into R
... expert at this, but you might consider trying MapReduce, which would basically mean taking a "divide and conquer" approach. R has several options for this, including:
mapReduce (pure R)
RHIPE (which uses Hadoop); see example 6.2.2 in the documentation for an example of subsetting files
Alterna...
When are you supposed to use escape instead of encodeURI / encodeURIComponent?
... section B.2.1.2 escape and the introduction text of Annex B says:
... All of the language features and behaviours specified in this annex have one or more undesirable characteristics and in the absence of legacy usage would be removed from this specification. ...
... Programmers should not us...
Transposing a NumPy array
...of a 1D array is still a 1D array! (If you're used to matlab, it fundamentally doesn't have a concept of a 1D array. Matlab's "1D" arrays are 2D.)
If you want to turn your 1D vector into a 2D array and then transpose it, just slice it with np.newaxis (or None, they're the same, newaxis is just mor...
Pythonic way to find maximum value and its index in a list?
...many options, for example:
import operator
index, value = max(enumerate(my_list), key=operator.itemgetter(1))
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