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MySQL - Rows to Columns
...temvalue |
+--------+----------+-----------+
| 1 | A | 10 |
| 1 | B | 3 |
| 2 | A | 9 |
| 2 | C | 40 |
+--------+----------+-----------+
This will be our goal, the pretty pivot table:
select * from history_itemvalue_piv...
Rename specific column(s) in pandas
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30
A much faster implementation would be to use list-comprehension if you need to rename a single c...
How to get unique values in an array
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120
Since I went on about it in the comments for @Rocket's answer, I may as well provide an example ...
Odd behavior when Java converts int to byte?
...mber is the positive version of that number
For example: 11111111 goes to 00000001 = -1. This is what Java will display as the value.
What you probably want to do is know the unsigned value of the byte.
You can accomplish this with a bitmask that deletes everything but the least significant 8 bit...
Is there a difference between x++ and ++x in java?
...
answered Jul 7 '09 at 21:09
Emil HEmil H
37.1k1010 gold badges7171 silver badges9494 bronze badges
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How do I get the time of day in javascript/Node.js?
...he getHours() method for the Date object.
getHours() return the time from 0 - 23, so make sure to deal with it accordingly. I think 0-23 is a bit more intuitive since military time runs from 0 - 23, but it's up to you.
With that in mind, the code would be something along the lines of:
var date = ...
When should I use Struct vs. OpenStruct?
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180
With an OpenStruct, you can arbitrarily create attributes. A Struct, on the other hand, must ha...
How to resize an image with OpenCV2.0 and Python2.6
I want to use OpenCV2.0 and Python2.6 to show resized images. I used and adopted this example but unfortunately, this code is for OpenCV2.1 and does not seem to be working on 2.0. Here my code:
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Is there a way to measure how sorted a list is?
...onsider the example sequence 9, 5, 7, 6. This sequence has the inversions (0,1), (0,2), (0,3), (2,3) and the inversion number 4.
If you want a value between 0 and 1, you can divide the inversion number by N choose 2.
To actually create an algorithm to compute this score for how sorted a list is, you...
How to find the sum of an array of numbers
... how can I find the sum of its elements? (In this case, the sum would be 10 .)
43 Answers
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