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Accessing last x characters of a string in Bash
I found out that with ${string:0:3} one can access the first 3 characters of a string. Is there a equivalently easy method to access the last three characters?
...
List of installed gems?
... >> Platform 0.4.0
# >> abstract 1.0.0
# >> actionmailer 3.0.5
# >> actionpack 3.0.5
# >> activemodel 3.0.5
# >> activerecord 3.0.5
Here's an updated way to get a list:
require 'rubygems'
def local_gems
Gem::Specification.sort_by{ |g| [g.name.downcase, g....
Programmatically creating Markdown tables in R with KnitR
...
Now knitr (since version 1.3) package include the kable function for a creation tables:
> library(knitr)
> kable(head(iris[,1:3]), format = "markdown")
| Sepal.Length| Sepal.Width| Petal.Length|
|-------------:|------------:|-------------:|
|...
SQL query return data from multiple tables
...what colors we have in the car yard.
mysql> create table colors(id int(3) not null auto_increment primary key,
-> color varchar(15), paint varchar(10));
Query OK, 0 rows affected (0.01 sec)
mysql> show columns from colors;
+-------+-------------+------+-----+---------+---------------...
Python 3 ImportError: No module named 'ConfigParser'
...
373
In Python 3, ConfigParser has been renamed to configparser for PEP 8 compliance. It looks like...
efficient circular buffer?
...in xrange(20):
... d.append(i)
...
>>> d
deque([10, 11, 12, 13, 14, 15, 16, 17, 18, 19], maxlen=10)
There is a recipe in the docs for deque that is similar to what you want. My assertion that it's the most efficient rests entirely on the fact that it's implemented in C by an incredib...
Extract a dplyr tbl column as a vector
...s2 %>% pull(5)
Resulting in...
[1] 21.0 21.0 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 17.8 16.4 17.3 15.2 10.4 10.4 14.7 32.4 30.4 33.9 21.5 15.5 15.2 13.3 19.2 27.3 26.0 30.4 15.8 19.7 15.0 21.4
And it also works fine with data frames:
> mtcars %>% pull(5)
[1] 3.90 3.90 3.85 3.08 3....
What does 'synchronized' mean?
...
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edited Mar 30 '18 at 7:18
Paolo Forgia
5,49477 gold badges3434 silver badges5555 bronze badges
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Installing Ruby Gem in Windows
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73
I recommend you just use rubyinstaller
It is recommended by the official Ruby page - see https:...