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How do you query for “is not null” in Mongo?
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This will return all documents with a key called "IMAGE URL", but they may still have a null value.
db.mycollection.find({"IMAGE URL":{$exists:true}});
This will return all documents with both a key called "IMAGE URL" and a non-null value.
d...
Is there any Rails function to check if a partial exists?
..., I'm using the following in my Rails 3/3.1 projects:
lookup_context.find_all('posts/_form').any?
The advantage over other solutions I've seen is that this will look in all view paths instead of just your rails root. This is important to me as I have a lot of rails engines.
This also works in R...
How to use filter, map, and reduce in Python 3
... longer return lists:
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map() and filter() return iterators. If you really need a list, a quick fix is e.g. list(map(...)), but a better fix is often to use a list comprehension (especially when the original code uses lambda), or rewriting the code so it doesn’t need a list at all. Particular...
Amazon S3 CORS (Cross-Origin Resource Sharing) and Firefox cross-domain font loading
...irefox not loading font from different origin than the current webpage. Usually, the issue arise when the fonts are served on CDNs.
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Mathematical functions in Swift
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UIKit, Cocoa, Foundation, all valid choices.
– erdekhayser
Nov 27 '14 at 20:26
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Get Character value from KeyCode in JavaScript… then trim
... get garbage. The problem is that keyCode does not correspond to ASCII for all characters. The ASCII character for semicolon is 59. Same issue is true of every special character, keyCode does NOT return the right code for String.fromCharCode().
– Alexander Tsepkov
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How to set custom favicon in Express?
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In Express 4
Install the favicon middleware and then do:
var favicon = require('serve-favicon');
app.use(favicon(__dirname + '/public/images/favicon.ico'));
Or better, using the path module:
app.use(favicon(path.join(__dirname,'public','ima...
How to show all shared libraries used by executables in Linux?
...to know which libraries are used by executables on my system. More specifically, I'd like to rank which libraries are used the most, along with the binaries that use them. How can I do this?
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ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'
I installed MySQL on Mac OS X Mountain Lion with homebrew install mysql , but when I tried mysql -u root I got the following error:
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Get Folder Size from Windows Command Line
...shell -noprofile -command "ls -r|measure -sum Length"
1 I do have a partially-finished bignum library in batch files somewhere which at least gets arbitrary-precision integer addition right. I should really release it, I guess :-)
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