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Combine two ActiveRecord::Relation objects
...
Relation objects can be converted to arrays. This negates being able to use any ActiveRecord methods on them afterwards, but I didn't need to. I did this:
name_relation = first_name_relation + last_name_relation
Ruby 1.9, rails 3.2
...
C/C++中的段错误（Segmentation fault） - C/C++ - 清泛网 - 专注C/C++及内核技术
...护，而不能任意访问。
例子1：
Code:
#include <stdio.h>
int main(){
int i=0;
scanf("%d",i);
printf("%d\n",i);
return 0;
}
编译和执行一下
$ gcc -o segerr segerr.c
$ ./segerr
10
段错误
咋一看，好像没有问题...
How do I reverse a C++ vector?
...der for this purpose.
#include <vector>
#include <algorithm>
int main() {
std::vector<int> a;
std::reverse(a.begin(), a.end());
return 0;
}
share
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improve this answer
...
Find an item in List by LINQ?
...
If you want the index of the element, this will do it:
int index = list.Select((item, i) => new { Item = item, Index = i })
.First(x => x.Item == search).Index;
// or
var tagged = list.Select((item, i) => new { Item = item, Index = i });
int index = (fro...
How can I read SMS messages from the device programmatically in Android?
...esult to prevent exception
do {
String msgData = "";
for(int idx=0;idx<cursor.getColumnCount();idx++)
{
msgData += " " + cursor.getColumnName(idx) + ":" + cursor.getString(idx);
}
// use msgData
} while (cursor.moveToNext());
} else {
// em...
Calculate size of Object in Java [duplicate]
...getObjectSize(o);
}
}
Use getObjectSize:
public class C {
private int x;
private int y;
public static void main(String [] args) {
System.out.println(ObjectSizeFetcher.getObjectSize(new C()));
}
}
Source
...
How to overcome TypeError: unhashable type: 'list'
...the other answers, the error is to due to k = list[0:j], where your key is converted to a list. One thing you could try is reworking your code to take advantage of the split function:
# Using with ensures that the file is properly closed when you're done
with open('filename.txt', 'rb') as f:
d = ...
Applying a function to every row of a table using dplyr?
...e is increasingly not recommended, although lots of people seem to find it intuitive. Do yourself a favour and go through Jenny Bryan's Row-oriented workflows in R with the tidyverse material to get a good handle on this topic.
The most straightforward way I have found is based on one of Hadley's e...
How do I expand a tuple into variadic template function's arguments?
...
Here's my code if anyone is interested
Basically at compile time the compiler will recursively unroll all arguments in various inclusive function calls <N> -> calls <N-1> -> calls ... -> calls <0> which is the last one and th...
How set background drawable programmatically in Android
...dy); is correct.
Another way to achieve it is to use the following:
final int sdk = android.os.Build.VERSION.SDK_INT;
if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
layout.setBackgroundDrawable(ContextCompat.getDrawable(context, R.drawable.ready) );
} else {
layout.setBackground(C...