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How do negative margins in CSS work and why is (margin-top:-5 != margin-bottom:5)?
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Negative margins are valid in css and understanding their (compliant) behaviour is mainly based on the box model and margin collapsing. While certain scenarios are more complex, a lot of common mistakes can be avoided after studying the spec.
For instance, r...
Find out how much memory is being used by an object in Python [duplicate]
...ject. One of the problems you may find is that Python objects - like lists and dicts - may have references to other python objects (in this case, what would your size be? The size containing the size of each object or not?). There are some pointers overhead and internal structures related to object ...
“Unable to find remote helper for 'https'” during git clone
...led when you compile git can cause this.
If you install (lib)curl-devel, and then rebuild/install git, this should solve the problem:
$ yum install curl-devel
$ # cd to wherever the source for git is
$ cd /usr/local/src/git-1.7.9
$ ./configure
$ make
$ make install
This worked for me on Cento...
Tab key == 4 spaces and auto-indent after curly braces in Vim
...use tabs (converting spaces to tabs, bad!), makes the tab key == 4 spaces, and automatically indent code after curly brace blocks like Emacs does?
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Compare floats in php
...same value do not need to actually be identical. So if $a is a literal .17 and $b arrives there through a calculation it can well be that they are different, albeit both display the same value.
Usually you never compare floating-point values for equality like this, you need to use a smallest accept...
Python unittest - opposite of assertRaises?
...r test must exit with a failure condition, not an error one. On the other hand, if in running the same code you would raise a KeyError, that would be an error, not a failure. In python - differently than some other languages - Exceptions are routinely used for control flow, this is why we have the e...
Flatten an irregular list of lists
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Using generator functions can make your example a little easier to read and probably boost the performance.
Python 2
def flatten(l):
for el in l:
if isinstance(el, collections.Iterable) and not isinstance(el, basestring):
for sub in flatten(el):
yield sub...
Should an Enum start with a 0 or a 1?
...ag enum values of zero unless the value represents "all flags are cleared" and is named appropriately, as prescribed by the next guideline.
✔️ DO name the zero value of flag enums None. For a flag enum, the value must always mean "all flags are cleared."
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How to append rows to an R data frame
...rs of the type you want for each column, insert values into those vectors, and then, at the end, create your data.frame.
Continuing with Julian's f3 (a preallocated data.frame) as the fastest option so far, defined as:
# pre-allocate space
f3 <- function(n){
df <- data.frame(x = numeric(n)...
Is a `=default` move constructor equivalent to a member-wise move constructor?
... same declared function type (except for possibly differing ref-qualifiers and except that in the case of a copy constructor or copy assignment operator, the parameter type may be “reference to non-const T”, where T is the name of the member function’s class) as if it had been implicitly decla...