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Are there disadvantages to using a generic varchar(255) for all text-based fields?
...hat in practice stored very short strings.
It's best to define the column based on the type of data that you intend to store. It has benefits to enforce application-related constraints, as other folks have mentioned. But it has the physical benefits to avoid the memory waste I described above.
I...
Convert columns to string in Pandas
... for help, clarification, or responding to other answers.Making statements based on opinion; back them up with references or personal experience.To learn more, see our tips on writing great answers.
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unsigned int vs. size_t
...ry model: Pointers are far (32-bit), but individual objects are limited to 64k (so size_t can be 16-bit).
– dan04
Nov 28 '10 at 3:46
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How to set JAVA_HOME in Linux for all users
... /etc/profile.d/jdk_home.sh:
#!/bin/sh
export JAVA_HOME=/opt/ibm/java-x86_64-60/
export PATH=$JAVA_HOME/bin:$PATH
I initially neglected the first line (the #!/bin/sh), and it won't work without it.
Now it's working:
$ echo $JAVA_HOME
/opt/ibm/java-x86_64-60/
...
Disable messages upon loading a package
...e:datasets"
[15] "package:methods" "Autoloads"
[17] "package:base"
R>
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Is there a NumPy function to return the first index of something in an array?
...
Just to add a very performant and handy numba alternative based on np.ndenumerate to find the first index:
from numba import njit
import numpy as np
@njit
def index(array, item):
for idx, val in np.ndenumerate(array):
if val == item:
return idx
# If no ...
IPC performance: Named Pipe vs Socket
...nted a project in C with named pipes, thanks to standart file input-output based communication (fopen, fprintf, fscanf ...) it was so easy and clean (if that is also a consideration).
I even coded them with java (I was serializing and sending objects over them!)
Named pipes has one disadvantage:
...
Get file size, image width and height before upload
...
Example using FileReader API
In case you need images sources as long Base64 encoded data strings
<img src="data:image/png;base64,iVBORw0KGg... ...lF/++TkSuQmCC=">
const EL_browse = document.getElementById('browse');
const EL_preview = document.getElementById('preview');
con...
Integer division with remainder in JavaScript?
...8 millisec
(a-(a%b))/b // -33, 0.6649 millisec
The above is based on 10 million trials for each.
Conclusion: Use (a/b>>0) (or (~~(a/b)) or (a/b|0)) to achieve about 20% gain in efficiency. Also keep in mind that they are all inconsistent with Math.floor, when a/b<0 &&...
Java Interfaces/Implementation naming convention [duplicate]
...sed. You could still come up with a better name than AbstractTruck and use BaseTruck or DefaultTruck instead since the abstract is in the definition. But since Abstract classes should never be part of any public facing interface I believe it is an acceptable exception to the rule. Making the constru...