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What is “entropy and information gain”?
.... P(m)=9/14 and P(f)=5/14. According to the definition of entropy:
Entropy_before = - (5/14)*log2(5/14) - (9/14)*log2(9/14) = 0.9403
Next we compare it with the entropy computed after considering the split by looking at two child branches. In the left branch of ends-vowel=1, we have:
Entropy_lef...
How do I get an apk file from an Android device?
...... /Users/bbb/Android/android-sdk-mac_86/tools/adb pull Android2.2Froyo/sdcard/iTwips.apk /Users/bbb Thanks is advance.......
– Finder
Oct 27 '10 at 13:17
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Ruby Hash to array of values
... Hash#values is not only simpler, but more efficient. Compare time ruby -e '(1..1000000).reduce({}){|h,i| h.store i,i; h}.values' with time ruby -e '(1..1000000).reduce({}){|h,i| h.store i,i; h}.map{|k,v| v}'
– jordanbtucker
Aug 2 '12 at 17:11
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Redis strings vs Redis hashes to represent JSON: efficiency?
...h other Objects, and you tend to only access a small subset of fields at a time, it might be better to go with option 2.
Advantages: considered a "good practice." Each Object is a full-blown Redis key. JSON parsing is fast, especially when you need to access many fields for this Object at once. Di...
Minimal web server using netcat
...ave my bash httpd launched by xinetd, xinetd tutorial. It also logs date, time, browser IP address, and the entire browser request to a log file, and calculates Content-Length for the Server header response.
user@machine:/usr/local/bin# cat ./bash_httpd
#!/bin/bash
x=0;
Log=$( echo -n "["$(date "+...
Difference between Divide and Conquer Algo and Dynamic Programming
...ivide and conquer:
Does more work on the sub-problems and hence has more time consumption.
In divide and conquer the sub-problems are independent of each other.
Dynamic programming:
Solves the sub-problems only once and then stores it in the table.
In dynamic programming the sub-problem are no...
Why is this F# code so slow?
A Levenshtein implementation in C# and F#. The C# version is 10 times faster for two strings of about 1500 chars. C#: 69 ms, F# 867 ms. Why? As far as I can tell, they do the exact same thing? Doesn't matter if it is a Release or a Debug build.
...
What is the difference between MySQL, MySQLi and PDO? [closed]
... There is often the confusion that for procedural you have to use mysql_*() functions where for OO you use mysqli! The fact is that mysqli completely replace the early (PHP 4) implementation of mysql. It is possible to use both the procedural style and the OO one with mysqli.
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How do you check if a variable is an array in JavaScript? [duplicate]
...re https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/isArray
variable instanceof Array
This method runs about 1/3 the speed as the first example. Still pretty solid, looks cleaner, if you're all about pretty code and not so much on performance. Note that check...
How can I shuffle the lines of a text file on the Unix command line or in a shell script?
...ely different. sort -R is deterministic. If you call it twice at different times on the same input you will get the same answer. shuf, on the other hand, produces randomized output, so it will most likely give different output on the same input.
– EfForEffort
F...