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Best way to merge two maps and sum the values of same key?
...> import Scalaz._
import Scalaz._
scala> val map1 = Map(1 -> 9 , 2 -> 20)
map1: scala.collection.immutable.Map[Int,Int] = Map(1 -> 9, 2 -> 20)
scala> val map2 = Map(1 -> 100, 3 -> 300)
map2: scala.collection.immutable.Map[Int,Int] = Map(1 -> 100, 3 -> 300)
scala&g...
When to use ' (or quote) in Lisp?
...uments passed to it are evaluated. This means you can write this:
(* (+ a 2)
3)
Which in turn evaluates (+ a 2), by evaluating a and 2. The value of the symbol a is looked up in the current variable binding set, and then replaced. Say a is currently bound to the value 3:
(let ((a 3))
(* (+...
Get decimal portion of a number with JavaScript
I have float numbers like 3.2 and 1.6 .
22 Answers
22
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ros 基本调试 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...。本文讲述了调试ROS的各种方法和必要步骤。目录1.简介2.可用的调试方法2.1通...原文地址：http://www.reactos.org/wiki/Debugging
欢迎拍砖。。
本文讲述了调试ROS的各种方法和必要步骤。
目录
1.简介
2.可用的调试方法
2.1通过文本...
Extracting the last n characters from a ruby string
... a one liner, you can put a number greater than the size of the string:
"123".split(//).last(5).to_s
For ruby 1.9+
"123".split(//).last(5).join("").to_s
For ruby 2.0+, join returns a string
"123".split(//).last(5).join
...
How to calculate a Mod b in Casio fx-991ES calculator
...
Now do your calculation (in comp mode), like 50 / 3 and you will see 16 2/3, thus, mod is 2. Or try 54 / 7 which is 7 5/7 (mod is 5).
If you don't see any fraction then the mod is 0 like 50 / 5 = 10 (mod is 0).
The remainder fraction is shown in reduced form, so 60 / 8 will result in 7 1/2. Rema...
How to redirect and append both stdout and stderr to a file with Bash?
...
2052
cmd >>file.txt 2>&1
Bash executes the redirects from left to right as follows:...
Bash set +x without it being printed
...o find a solution that doesn't use a subshell:
set -x
command
{ set +x; } 2>/dev/null
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Uninstall all installed gems, in OSX?
...
Rubygems >= 2.1.0
gem uninstall -aIx
a removes all versions
I ignores dependencies
x includes executables
Rubgems < 2.1.0
for i in `gem list --no-versions`; do gem uninstall -aIx $i; done
...