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What is an idempotent operation?
...ng, an idempotent operation is one that has no additional effect if it is called more than once with the same input parameters. For example, removing an item from a set can be considered an idempotent operation on the set.
In mathematics, an idempotent operation is one where f(f(x)) = f(x). For exa...
How to get an array of specific “key” in multidimensional array without looping
...s = array_map(function ($ar) {return $ar['id'];}, $users);
Before(Technically php 4.0.6+), you must create an anonymous function with create_function instead:
$ids = array_map(create_function('$ar', 'return $ar["id"];'), $users);
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Skip rows during csv import pandas
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^ No need to import at all, it is directly accessible as pd.compat.StringIO .
– cs95
Apr 8 '19 at 17:51
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Print list without brackets in a single row
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print(', '.join(names))
This, like it sounds, just takes all the elements of the list and joins them with ', '.
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How to do a JUnit assert on a message in a logger
I have some code-under-test that calls on a Java logger to report its status.
In the JUnit test code, I would like to verify that the correct log entry was made in this logger. Something along the following lines:
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How can I create a copy of an object in Python?
...would like to create a copy of an object. I want the new object to possess all properties of the old object (values of the fields). But I want to have independent objects. So, if I change values of the fields of the new object, the old object should not be affected by that.
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Git: How do I list only local branches?
... dialects of English that I'm familiar with, "list only local branches" usually parses as "list only those branches that are local". (To say "list those branches that are only local", I would say "list local-only branches".)
– Mathieu K.
Mar 16 '18 at 2:46
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How to find the kth smallest element in the union of two sorted arrays?
...the demonstration you can use the loop invariant i + j = k, but I won't do all your homework :)
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How do you run a command for each line of a file?
...teractive processing (sample)
Regarding the OP request: running chmod on all targets listed in file, xargs is the indicated tool. But for some other applications, small amount of files, etc...
Read entire file as command line argument.
If your file is not too big and all files are well named (w...
Most efficient conversion of ResultSet to JSON?
...tests. You could probably make it more elegant with a HashMap lookup to a callback but I doubt it would be any faster. As to memory, this is pretty slim as is.
Somehow I doubt this code is actually a critical bottle neck for memory or performance. Do you have any real reason to try to optimize it?...