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How do I know if a generator is empty from the start?
..., there is no simple way. There are a whole lot of work-arounds.
There really shouldn't be a simple way, because of what generators are: a way to output a sequence of values without holding the sequence in memory. So there's no backward traversal.
You could write a has_next function or maybe eve...
Python argparse mutual exclusive group
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add_mutually_exclusive_group doesn't make an entire group mutually exclusive. It makes options within the group mutually exclusive.
What you're looking for is subcommands. Instead of prog [ -a xxxx | [-b yyy -c zzz]], you'd have:
p...
Comparing mongoose _id and strings
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The accepted answers really limit what you can do with your code. For example, you would not be able to search an array of Object Ids by using the equals method. Instead, it would make more sense to always cast to string and compare the keys.
Her...
Is Big O(logn) log base e?
...nary search tree type of data structures, I see the Big O notation is typically noted as O(logn). With a lowercase 'l' in log, does this imply log base e (n) as described by the natural logarithm? Sorry for the simple question but I've always had trouble distinguishing between the different impli...
How can I get a precise time, for example in milliseconds in Objective-C?
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Actually this is precise enough for the general use case.
– logancautrell
Jul 2 '12 at 12:30
4
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Query for documents where array size is greater than 1
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Great, that was perfect thank you. Although I actually have some documents that don't have a name so had to modify the query to be: db.accommodations.find( { $where: "if (this.name && this.name.length > 1) {return this; } "} );
– emson
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Python json.loads shows ValueError: Extra data
...) # == json.loads(json.dumps({}) + json.dumps({}))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "C:\Python27\lib\json\__init__.py", line 338, in loads
return _default_decoder.decode(s)
File "C:\Python27\lib\json\decoder.py", line 368, in decode
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Getting the first character of a string with $str[0]
...am just not sure whether this is 'good practice', as that notation is generally used with arrays. This feature doesn't seem to be very well documented so I'm turning to you guys to tell me if it's all right – in all respects – to use this notation?
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Best way to test if a row exists in a MySQL table
...RE ...)
and per the documentation, you can SELECT anything.
Traditionally, an EXISTS subquery starts with SELECT *, but it could
begin with SELECT 5 or SELECT column1 or anything at all. MySQL
ignores the SELECT list in such a subquery, so it makes no difference.
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In where shall I use isset() and !empty()
... it's not a good idea to use this operator for math in case "0" is accidentally a string. This can be dangerous. Instead, use basic >, < and == operators and convert variables using intval() or floatval().
– kaleazy
Feb 14 at 18:08
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