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HashMap get/put complexity
We are used to saying that HashMap get/put operations are O(1). However it depends on the hash implementation. The default object hash is actually the internal address in the JVM heap. Are we sure it is good enough to claim that the get/put are O(1) ?
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Why are elementwise additions much faster in separate loops than in a combined loop?
Suppose a1 , b1 , c1 , and d1 point to heap memory and my numerical code has the following core loop.
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Getting the count of unique values in a column in bash
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153
To see a frequency count for column two (for example):
awk -F '\t' '{print $2}' * | sort | un...
How can I get Docker Linux container information from within the container itself?
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How can I extract a good quality JPEG image from a video file with ffmpeg?
...le:v (or the alias -q:v) as an output option.
Normal range for JPEG is 2-31 with 31 being the worst quality.
The scale is linear with double the qscale being roughly half the bitrate.
Recommend trying values of 2-5.
You can use a value of 1 but you must add the -qmin 1 output option (because the de...
What is the JavaScript >>> operator and how do you use it?
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It doesn't just convert non-Numbers to Number, it converts them to Numbers that can be expresse...
Check if a string contains an element from a list (of strings)
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Best way to simulate “group by” from bash?
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Finding median of list in Python
...ated by taking the average of the two middle values:
>>> median([1, 3, 5])
3
>>> median([1, 3, 5, 7])
4.0
Usage:
import statistics
items = [6, 1, 8, 2, 3]
statistics.median(items)
#>>> 3
It's pretty careful with types, too:
statistics.median(map(float, items))
#&...
How to reshape data from long to wide format
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