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Paste multiple columns together
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no need for apply here; paste is vectorised, and that's more efficient
– baptiste
Jan 28 '13 at 21:49
1
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Should I use char** argv or char* argv[]?
I'm just learning C and was wondering which one of these I should use in my main method. Is there any difference? Which one is more common?
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How can I convert an RGB image into grayscale in Python?
I'm trying to use matplotlib to read in an RGB image and convert it to grayscale.
12 Answers
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PostgreSQL database default location on Linux
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The "directory where postgresql will keep all databases" (and configuration) is called "data directory" and corresponds to what PostgreSQL calls (a little confusingly) a "database cluster", which is not related to distributed computing, it just means a group of databases and related...
Is there a Java equivalent to C#'s 'yield' keyword?
...ons I know of is Aviad Ben Dov's infomancers-collections library from 2007 and Jim Blackler's YieldAdapter library from 2008 (which is also mentioned in the other answer).
Both will allow you to write code with yield return-like construct in Java, so both will satisfy your request. The notable diff...
Pure JavaScript: a function like jQuery's isNumeric() [duplicate]
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@Matt My comment was aimed at the comment and the note in the answer stating parseInt was the wrong way of doing this (then going ahead and using parseFloat, which doesn't really seem different). Interestingly isFinite will get you the result you're after in almost a...
Only using @JsonIgnore during serialization, but not deserialization
I have a user object that is sent to and from the server. When I send out the user object, I don't want to send the hashed password to the client. So, I added @JsonIgnore on the password property, but this also blocks it from being deserialized into the password that makes it hard to sign up users...
Connect Java to a MySQL database
...(DataSource) context.lookup("java:comp/env/jdbc/myDB");
or instantiating and configuring one from your database driver directly:
MysqlDataSource dataSource = new MysqlDataSource();
dataSource.setUser("scott");
dataSource.setPassword("tiger");
dataSource.setServerName("myDBHost.example.org");
an...
How to check if an object is a list or tuple (but not string)?
...es I stumbled upon bugs where a function passes a str object by mistake, and the target function does for x in lst assuming that lst is actually a list or tuple .
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git diff renamed file
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The issue with the difference between HEAD^^ and HEAD is that you have an a.txt in both commits, so just considering those two commits (which is what diff does), there is no rename, there is a copy and a change.
To detect copies, you can use -C:
git diff -C HEAD^^ HEA...