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What do the terms “CPU bound” and “I/O bound” mean?
...ght become I/O bound, since the bottleneck is then the reading of the data from disk (actually, this example is perhaps kind of old-fashioned these days with hundreds of MB/s coming in from SSDs).
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How to read all files in a folder from Java?
...e/you/Desktop");
listFilesForFolder(folder);
Files.walk API is available from Java 8.
try (Stream<Path> paths = Files.walk(Paths.get("/home/you/Desktop"))) {
paths
.filter(Files::isRegularFile)
.forEach(System.out::println);
}
The example uses try-with-resources patte...
cartesian product in pandas
... you can produce a cartesian product using merge (like you would in SQL).
from pandas import DataFrame, merge
df1 = DataFrame({'key':[1,1], 'col1':[1,2],'col2':[3,4]})
df2 = DataFrame({'key':[1,1], 'col3':[5,6]})
merge(df1, df2,on='key')[['col1', 'col2', 'col3']]
Output:
col1 col2 col3
0 ...
When to use PNG or JPG in iPhone development?
... extra CPU energy to display. However, large PNGs may take longer to read from storage than more compressed image formats, and thus be slower to display.
JPG's are smaller to store, but lossy (amount depends on compression level), and to display them requires a much more complicated decoding algor...
How to override trait function and call it from the overridden function?
...n calc($v) {
return parent::calc($v*3);
}
}
// .... other code from above
print (new MyTraitChildClass())->calc(2); // will print 8 (2*3 + 2)
You can also provide for ways to override, but still access the trait method as follows:
trait A {
function trait_calc($v) {
ret...
How can I lock a file using java (if possible)
... opens a file using a FileReader. How can I prevent another (Java) process from opening this file, or at least notify that second process that the file is already opened? Does this automatically make the second process get an exception if the file is open (which solves my problem) or do I have to ex...
How can I check file size in Python?
....stat. You can get it by either using pathlib (Python 3.4+):
>>> from pathlib import Path
>>> Path('somefile.txt').stat()
os.stat_result(st_mode=33188, st_ino=6419862, st_dev=16777220, st_nlink=1, st_uid=501, st_gid=20, st_size=1564, st_atime=1584299303, st_mtime=1584299400, st_ct...
map vs. hash_map in C++
...characteristics (e.g. it is stored in sorted order, which allows traversal from start to finish). unordered_map will be faster on insert and delete than a map.
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How to get a enum value from string in C#?
...L_MACHINE", true);
This code snippet illustrates obtaining an enum value from a string. To convert from a string, you need to use the static Enum.Parse() method, which takes 3 parameters. The first is the type of enum you want to consider. The syntax is the keyword typeof() followed by the name of...
what is the difference between a portlet and a servlet?
...hat regulates portal containers and components. This is different standard from standards for web containers (and servlets). Though there are definitely strong parallels between these two standards they differ in containers, APIs, life cycle, configuration, deployment, etc.
The main difference bet...