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What is the “-->” operator in C++?
...
+100
It's equivalent to
while (x-- > 0)
x-- (post decrement) is equivalent to x = x-1 so, the code transforms to:
while(x > 0) ...
Modifying a subset of rows in a pandas dataframe
...ease, use NumPy's where function.
Setup
Create a two-column DataFrame with 100,000 rows with some zeros.
df = pd.DataFrame(np.random.randint(0,3, (100000,2)), columns=list('ab'))
Fast solution with numpy.where
df['b'] = np.where(df.a.values == 0, np.nan, df.b.values)
Timings
%timeit df['b'] = np.w...
How can I output leading zeros in Ruby?
...
filenames = '000'.upto('100').map { |index| "file_#{index}" }
Outputs
[file_000, file_001, file_002, file_003, ..., file_098, file_099, file_100]
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...
How can I read command line parameters from an R script?
...ogram Files\R-3.0.2\bin\RScript.exe"
%R_Script% exmpl.R 2010-01-28 example 100 > exmpl.batch 2>&1
Alternatively, using Rterm.exe:
set R_TERM="C:\Program Files\R-3.0.2\bin\i386\Rterm.exe"
%R_TERM% --no-restore --no-save --args 2010-01-28 example 100 < exmpl.R > exmpl.batch 2>&am...
Interface Builder: What are the UIView's Layout iOS 6/7 Deltas for?
...bit more clear:
<inset key="insetFor6xAndEarlier" minX="-50" minY="-100" maxX="-50" maxY="300"/>
The key name insetFor6xAndEarlier explicitly states what this does; you can provide alternative insets for UI elements when run on iOS 7's predecessors. For example, the above defines the fol...
Is there a `pointer-events:hoverOnly` or similar in CSS?
...;
height: 300px;
}
#overlay {
background-color: black;
width: 100%;
height: 100%;
opacity: 0;
z-index: 1;
/* Pass through clicks */
pointer-events: none;
}
/*
Set overlay hover style based on
:hover pseudo-element of its
container
*/
#container:hove...
How can I get every nth item from a List?
...ne in a linq friendly manner then you could lazily eval and take the first 100 value eg `` source.TakeEvery(5).Take(100) `` If the underlying source was expensive to eval then your approach would cause every element to be evaluated
– RhysC
Dec 11 '15 at 6:4...
possible EventEmitter memory leak detected
...Listeners via:
const emitter = new EventEmitter()
emitter.setMaxListeners(100)
// or 0 to turn off the limit
emitter.setMaxListeners(0)
But if it's not your code you can use the trick to increase the default limit globally:
require('events').EventEmitter.prototype._maxListeners = 100;
Of cours...
STL中map容器使用自定义key类型报错详解 - C/C++ - 清泛网 - 专注C/C++及内核技术
... int m_a;
};
...
map<a, int> mp;
a a1;
a1.m_a = 100;
a1.pName = "a1";
a a2;
a2.m_a = 200;
a2.pName = "a2";
mp.insert(std::make_pair(a1, 1));
mp.insert(std::make_pair(a2, 1));
编译出错
初始化结构体对象，添加到容器...
Simple way to repeat a String in java
...tidy way to do this in conjunction with Collections.nCopies:
// say hello 100 times
System.out.println(String.join("", Collections.nCopies(100, "hello")));
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