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Specify format for input arguments argparse python
...rsions to be performed ... type= can take any callable that takes a single string argument and returns the converted value
You could do something like:
def valid_date(s):
try:
return datetime.strptime(s, "%Y-%m-%d")
except ValueError:
msg = "Not a valid date: '{0}'.".forma...
Copy a file in a sane, safe and efficient way
...; src.rdbuf();
}
This is so simple and intuitive to read it is worth the extra cost. If we were doing it a lot, better to fall back on OS calls to the file system. I am sure boost has a copy file method in its filesystem class.
There is a C method for interacting with the file system:
#include ...
SQLAlchemy: Creating vs. Reusing a Session
... of expire_on_commit pretty much optional, as this flag can incur a lot of extra SQL for an operation that calls commit() in the middle of a series of operations. Not sure if this answers your question.
The next round is what you mention about threading. If your app is multithreaded, we recomme...
How do I bind a WPF DataGrid to a variable number of columns?
... {
Header = column.Name,
Binding = new Binding(string.Format("[{0}]", index++))
});
}
}
// E.g. myGrid.GenerateColumns(schema);
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Learning Python from Ruby; Differences and Similarities
...rate using multiple indexes. For example, to find all the palindromes in a string (assuming you have a function p() that returns true for palindromes), all you need is a single list comprehension:
s = 'string-with-palindromes-like-abbalabba'
l = len(s)
[s[x:y] for x in range(l) for y in range(x,l+1...
Printing everything except the first field with awk
...for loop:
awk '{for (i=2; i<=NF; i++) print $i}' filename
So if your string was "one two three", the output will be:
two
three
If you want the result in one row, you could do as follows:
awk '{for (i=2; i<NF; i++) printf $i " "; print $NF}' filename
This will give you: "two three"
...
SQL Server equivalent to MySQL enum data type?
... then you'll end-up adding lots of tables to your database. Not to mention extra IO reads due to FK constraint-checking when inserting/deleting data, whereas a CHECK CONSTRAINT is much faster and doesn't cause database object spam.
– Dai
Sep 18 at 7:23
...
Which is more efficient: Multiple MySQL tables or one large table?
...ow on top of a legacy system. I had to expand the old database tables with extra columns. I decided to make new tables for the new data. Some new features come in handy for the legacy system and now I can easily integrate them without having to rewrite too much of the old queries
...
Rails where condition using NOT NIL
...S NOT NULL
Note that this syntax reports a deprecation (it talks about a string SQL snippet, but I guess the hash condition is changed to string in the parser?), so be sure to add the references to the end:
Foo.includes(:bar).where.not(bars: {id: nil}).references(:bar)
DEPRECATION WARNING: I...
How do I compare two strings in Perl?
How do I compare two strings in Perl?
6 Answers
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