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Only read selected columns
...g","Sep","Oct","Nov","Dec"))
dat <- fread("data.txt", drop = c(8:13))
All result in:
> data
Year Jan Feb Mar Apr May Jun
1 2009 -41 -27 -25 -31 -31 -39
2 2010 -41 -27 -25 -31 -31 -39
3 2011 -21 -27 -2 -6 -10 -32
UPDATE: When you don't want fread to return a data.table, use the data.ta...
Iterating over each line of ls -l output
... instead of parsing output of "ls -l" line by line, you could iterate over all files and do an "ls -l" for each individual file like this:
for x in * ; do echo `ls -ld $x` ; done
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Iterating C++ vector from the end to the beginning
...;
i != my_vector.rend(); ++i ) {
}
rbegin()/rend() were especially designed for that purpose. (And yes, incrementing a reverse_interator moves it backward.)
Now, in theory, your method (using begin()/end() & --i) would work, std::vector's iterator being bidirectional, but remember,...
Generate random numbers using C++11 random library
... functions and why not to use rand(). In it, he included a slide that basically solves your question. I've copied the code from that slide below.
You can see his full talk here: http://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful
#include <random>
#include <iostream&g...
How to set java_home on Windows 7?
...
Find JDK Installation Directory
First you need to know the installation path for the Java Development Kit.
Open the default installation path for the JDK:
C:\Program Files\Java
There should be a subdirectory like:
C:\Program Files\J...
搭建高可用mongodb集群（二）—— 副本集 - 大数据 & AI - 清泛网 - 专注C/...
...(config);
#输出成功
{
"info" : "Config now saved locally. Should come online in about a minute.",
"ok" : 1
}
#查看日志，副本集启动成功后，138为主节点PRIMARY，136、137为副本节点SECONDARY。
Sun Dec 29 20:26:13.842 [conn3] replSet repl...
Using numpy to build an array of all combinations of two arrays
...
It should be noted that meshgrid only works for smaller range sets, I have a large one and I get error: ValueError: maximum supported dimension for an ndarray is 32, found 69
– mikkom
Oct 20 '19 at 6:54
...
Rename MySQL database [duplicate]
...atabase with the database name you wanted.
The short, quick steps without all the above explanation are:
mysqldump -u root -p original_database > original_database.sql
mysql -u root -p -e "create database my_new_database"
mysql -u root -p my_new_database < original_database.sql
mysql -u roo...
One SVN repository or many?
... its own tags, trunk and branches. If one gets too big or I need to physically isolate a customer's code for their comfort, I can quickly and easily create a new repository.
I recently consulted with a relatively large firm on migrating multiple source code control systems to Subversion. They have...
How to set IntelliJ IDEA Project SDK
I just installed IntelliJ IDEA and when I try to create my first Project it asks for me to set up the Project SDK. When I click on "JDK" it asks for me to select the home directory of the JDK as shown in this image.
...