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Empty arrays seem to equal true and false at the same time
...t (Array is instance of Object in JS) will check if the object is present, and returns true/false.
When you call if (arr == false) you compare values of this object and the primitive false value. Internally, arr.toString() is called, which returns an empty string "".
This is because toString cal...
Big-O for Eight Year Olds? [duplicate]
I'm asking more about what this means to my code. I understand the concepts mathematically, I just have a hard time wrapping my head around what they mean conceptually. For example, if one were to perform an O(1) operation on a data structure, I understand that the number of operations it has to p...
SQL order string as number
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and if you have mixed string and number and want them both sorted, use "order by col * 1, col"
– Hayden Thring
Feb 23 '15 at 3:42
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Error handling in getJSON calls
How can you handle errors in a getJSON call? Im trying to reference a cross-domain script service using jsonp, how do you register an error method?
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cscope or ctags why choose one over the other? [closed]
I primarily use vim / gvim as an editor and am looking at using a combination of lxr (the Linux Cross Reference) and either cscope or ctags for exploring the kernel source. However, I haven't ever used either cscope or ctags and would like to hear why one might choose one over the other t...
Regex - how to match everything except a particular pattern
...particular pattern? I'm faced with a situation where I have to match an (A and ~B) pattern.
8 Answers
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Bad class file magic or version
I already know that question has been already asked very often and answers, but no one of the answers i found fixed my problem.
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What's a concise way to check that environment variables are set in a Unix shell script?
...(an empty string) is OK — not exactly what you want, but the alternative and older notation.
The second variant (using :?) requires DEST to be set and non-empty.
If you supply no message, the shell provides a default message.
The ${var?} construct is portable back to Version 7 UNIX and the Bourne ...
How I can I lazily read multiple JSON values from a file/stream in Python?
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Here's a much, much simpler solution. The secret is to try, fail, and use the information in the exception to parse correctly. The only limitation is the file must be seekable.
def stream_read_json(fn):
import json
start_pos = 0
with open(fn, 'r') as f:
while True:
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Keep file in a Git repo, but don't track changes
...t solution to do this. First change the file you do not want to be tracked and use the following command:
git update-index --assume-unchanged FILE_NAME
and if you want to track the changes again use this command:
git update-index --no-assume-unchanged FILE_NAME
git-update-index documentation...