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'and' (boolean) vs '&' (bitwise) - Why difference in behavior with lists vs numpy arrays?
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and tests whether both expressions are logically True while & (when used with True/False values) tests if both are True.
In Python, empty built-in objects are typically treated as logically False while non-empty built-ins are logically True. This facilitates the c...
Getting the last element of a list
...at should happen when attempting to get an element from an empty list. For Strings astr[-1:] could be a valid approach since it returns the same type as astr[-1], but I don't think the ':' helps to deal with empty lists (and the question is about lists). If the idea is to use "alist[-1:]" as a condi...
Reference - What does this error mean in PHP?
...m. (Note: You might have multiple blocks if you had code that was automatically constructed)
Also make sure you don't have any Byte Order Marks in your code, for example when the encoding of the script is UTF-8 with BOM.
Related Questions:
Headers already sent by PHP
All PHP "Headers already sen...
Store print_r result into a variable as a string or text
...flow.com%2fquestions%2f9325067%2fstore-print-r-result-into-a-variable-as-a-string-or-text%23new-answer', 'question_page');
}
);
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What do the terms “CPU bound” and “I/O bound” mean?
...U (doing calculations). A program that computes new digits of π will typically be CPU-bound, it's just crunching numbers.
A program is I/O bound if it would go faster if the I/O subsystem was faster. Which exact I/O system is meant can vary; I typically associate it with disk, but of course networ...
Git: Set up a fetch-only remote?
... I went with git remote set-url --push origin -- --read-only-- -- note the extra -- to allow a name with leading dashes. This felt more readable to me.
– lindes
Dec 17 '16 at 1:03
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Authorize a non-admin developer in Xcode / Mac OS
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Finally, I was able to get rid of it using DevToolsSecurity -enable on Terminal.
Thanks to @joar_at_work!
FYI: I'm on Xcode 4.3, and pressed the disable button when it launched for the first time, don't ask why, just assume my ...
Dynamically select data frame columns using $ and a character value
...e that must first be evaluated in the second argument. You may only pass a string which is never evaluated.
Instead use [ (or [[ if you want to extract only a single column as a vector).
For example,
var <- "mpg"
#Doesn't work
mtcars$var
#These both work, but note that what they return is d...
How to think in data stores instead of databases?
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The datastore makes no distinction between inserts and updates. When you call put() on an entity, that entity gets stored to the datastore with its unique key, and anything that has that key gets overwritten. Basically, each entity kind in the datastore acts like an enormous map or sorted list.
Que...
Difference between var_dump,var_export & print_r
...lt.
// var_dump(array('', false, 42, array('42')));
array(4) {
[0]=> string(0) ""
[1]=> bool(false)
[2]=> int(42)
[3]=> array(1) {[0]=>string(2) "42")}
}
print_r is for debugging purposes, too, but does not include the member's type. It's a good idea to use if you know the ...