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How to join (merge) data frames (inner, outer, left, right)
...rge; it's safer if the input data.frames change unexpectedly and easier to read later on.
You can merge on multiple columns by giving by a vector, e.g., by = c("CustomerId", "OrderId").
If the column names to merge on are not the same, you can specify, e.g., by.x = "CustomerId_in_df1", by.y = "Cu...
What is the gain from declaring a method as static
... members that you do not intend to use.
And moreover, it will help people reading your code understand the nature of the contract.
That's why it's considered good to declare a method static when it's actually implementing a static contract.
In some cases, your method only means something relative...
Return first match of Ruby regex
...ature documented in String#[]. Thanks for asking about the doc, because in reading it I found the capture argument – which lets you return a capture instead of the full match.
– slothbear
Jul 11 '14 at 13:02
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MySQL connection not working: 2002 No such file or directory
...hp5.so
Start Apache HTTP with sudo apachectl start (or restart if it's already started and needs to be restarted to re-read the configuration file).
Make sure that /var/log/apache2/error_log contains a line that tells you the php5_module is enabled - you should see PHP/5.3.15 (or similar).
[noti...
Why does sun.misc.Unsafe exist, and how can it be used in the real world?
...eal JNI calls into native code that contains special instructions for CAS
read more about CAS here http://en.wikipedia.org/wiki/Compare-and-swap
The sun.misc.Unsafe functionality of the host VM can be used to allocate uninitialized objects and then interpret the constructor invocation as any other ...
What is the difference between Normalize.css and Reset CSS?
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@Jitendra Vyas: -- there is really only one way: read the well-commented Normalize.CSS code, and decide if it's a good fit for your needs or not. github.com/necolas/normalize.css/blob/master/normalize.css
– Jesper M
Aug 1 '11 at 16:46
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What's the difference between io.sockets.emit and broadcast?
... the newly created connection
This Socket.IO Wiki post will help everyone reading this question:
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What is sys.maxint in Python 3?
I've been trying to find out how to represent a maximum integer, and I've read to use "sys.maxint" . However, in Python 3 when I call it I get:
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Adding a y-axis label to secondary y-axis in matplotlib
...with matplotlib: just pandas.
Tweaking the original example:
table = sql.read_frame(query,connection)
ax = table[0].plot(color=colors[0],ylim=(0,100))
ax2 = table[1].plot(secondary_y=True,color=colors[1], ax=ax)
ax.set_ylabel('Left axes label')
ax2.set_ylabel('Right axes label')
Basically, whe...
Explanation of JSONB introduced by PostgreSQL
PostgreSQL just introduced JSONB and it's already trending on hacker news . It would be great if someone could explain how it's different from Hstore and JSON previously present in PostgreSQL. What are its advantages and limitations and when should someone consider using it?
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