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Update MongoDB field using value of another field
...ion 4.2+ which allows using of aggregation pipeline in the update document and the updateOne, updateMany or update collection method. Note that the latter has been deprecated in most if not all languages drivers.
MongoDB 4.2+
Version 4.2 also introduced the $set pipeline stage operator which is an...
How is “int main(){(([](){})());}” valid C++?
...tart from the beginning: [](){} is an empty lambda expression.
Then, in C and C++, you can wrap expressions in parens and they behave exactly the same† as if written without them, so that's what the first pair of parens around the lambda does. We're now at ([](){}).
Then, () after the first wrap...
Multiple levels of 'collection.defaultdict' in Python
...possibilities offered by collections.defaultdict , notably in readability and speed. I have put them to use with success.
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Why am I seeing “TypeError: string indices must be integers”?
I'm playing with both learning python and trying to get github issues into a readable form. Using the advice on How can I convert JSON to CSV? I came up with this:
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How to find the last field using 'cut'
....google.com" to be moc.elgoog.spam
cut uses dot (ie '.') as the delimiter, and chooses the first field, which is moc
lastly, we reverse it again to get com
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How to write DataFrame to postgres table?
There is DataFrame.to_sql method, but it works only for mysql, sqlite and oracle databases. I cant pass to this method postgres connection or sqlalchemy engine.
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How do I build a numpy array from a generator?
...ping this in mind, it is technically impossible to take a generator object and turn it into an array unless you either:
can predict how many elements it will yield when run:
my_array = numpy.empty(predict_length())
for i, el in enumerate(gimme()): my_array[i] = el
are willing to store its elemen...
How to list containers in Docker
There's a command to list images, docker images , but there doesn't seem to be a corresponding docker containers .
14 Ans...
How to do a SOAP Web Service call from Java class?
I'm relative new to the webservices world and my research seems to have confused me more than enlighten me, my problem is that I was given a library(jar) which I have to extend with some webservice functionality.
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Vertically align text next to an image?
Why won't vertical-align: middle work? And yet, vertical-align: top does work.
23 Answers
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