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MongoDB atomic “findOrCreate”: findOne, insert if nonexistent, but do not update
as the title says, I want to perform a find (one) for a document, by _id, and if doesn't exist, have it created, then whether it was found or was created, have it returned in the callback.
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Can gcc output C code after preprocessing?
...tenate lines, choke on special characters, etc.) Asuming you have gcc installed, the command line is:
gcc -E -x c -P -C -traditional-cpp code_before.cpp > code_after.cpp
(Doesn't have to be 'cpp'.) There's an excellent description of this usage at http://www.cs.tut.fi/~jkorpela/html/cpre.htm...
Make a Bash alias that takes a parameter?
...reate a function.
alias does not accept parameters but a function can be called just like an alias. For example:
myfunction() {
#do things with parameters like $1 such as
mv "$1" "$1.bak"
cp "$2" "$1"
}
myfunction old.conf new.conf #calls `myfunction`
By the way, Bash functions def...
How can I list all foreign keys referencing a given table in SQL Server?
...highly referenced table in a SQL Server database. How can I get a list of all the foreign key constraints I will need to remove in order to drop the table?
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How to find all occurrences of a substring?
Python has string.find() and string.rfind() to get the index of a substring in a string.
20 Answers
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Convert unix time to readable date in pandas dataframe
...12.15
3 1349979305 12.19
4 1350065705 12.15
In [25]: df['date'] = pd.to_datetime(df['date'],unit='s')
In [26]: df.head()
Out[26]:
date price
0 2012-10-08 18:15:05 12.08
1 2012-10-09 18:15:05 12.35
2 2012-10-10 18:15:05 12.15
3 2012-10-11 18:15:05 12.19
4 2012-10-12 18:15:...
What is the meaning of the /dist directory in open source projects?
Since I first saw a dist/ directory in many open source projects, usually on GitHub, I've been wondering what it means.
4...
How to avoid Dependency Injection constructor madness?
..., more coarse-grained interface that hides the interaction between some or all of the fine-grained dependencies you currently require.
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Unable to locate tools.jar
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Add JAVA_HOME and the /bin directory to your path. You realize that this answer is two years old, right?
– duffymo
Jul 23 '13 at 12:52
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Search all of Git history for a string? [duplicate]
...)
git log -S password
This will find any commit that added or removed the string password. Here a few options:
-p: will show the diffs. If you provide a file (-p file), it will generate a patch for you.
-G: looks for differences whose added or removed line matches the given regexp, as opposed to -...