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ValueError: setting an array element with a sequence
...9 when building an array of objects (not necessarily lists) that implement __getitem__ as specified here:github.com/numpy/numpy/issues/5100
– dashesy
Nov 21 '14 at 19:13
add a...
How to forward declare a template class in namespace std?
...served for use by the implementation, so you should use something like TEST_H instead of __TEST__. It's not going to generate a warning or an error, but if your program has a clash with an implementation-defined identifier, then it's not guaranteed to compile or run correctly: it's ill-formed. Also ...
Docker - how can I copy a file from an image to a host?
...
Actually, I use docker run --rm --entrypoint tar _image_ cC _img_directory_ . | tar xvC _host_directory_
– caligari
Nov 30 '17 at 11:04
add a comment...
What should my Objective-C singleton look like? [closed]
... below, I think you should be doing:
+ (id)sharedFoo
{
static dispatch_once_t once;
static MyFoo *sharedFoo;
dispatch_once(&once, ^ { sharedFoo = [[self alloc] init]; });
return sharedFoo;
}
share
...
What kind of leaks does automatic reference counting in Objective-C not prevent or minimize?
...chain referring back to an earlier object.
It is for this reason that the __unsafe_unretained and __weak ownership qualifiers exist. The former will not retain any object it points to, but leaves open the possibility of that object going away and it pointing to bad memory, whereas the latter doesn...
How do synchronized static methods work in Java and can I use it for loading Hibernate entities?
...ic methods, you can
class SomeClass {
private static final Object LOCK_1 = new Object() {};
private static final Object LOCK_2 = new Object() {};
static void foo() {
synchronized(LOCK_1) {...}
}
static void fee() {
synchronized(LOCK_1) {...}
}
static void...
Bash empty array expansion with `set -u`
...4.4.
$ bash --version | head -n 1
GNU bash, version 4.4.19(1)-release (x86_64-pc-linux-gnu)
$ set -u
$ arr=()
$ echo "foo: '${arr[@]}'"
foo: ''
There is a conditional you can use inline to achieve what you want in older versions: Use ${arr[@]+"${arr[@]}"} instead of "${arr[@]}".
$ function ...
Shell脚本编程30分钟入门 - 更多技术 - 清泛网 - 专注C/C++及内核技术
Shell脚本编程30分钟入门linux_shell_30min_guides什么是Shell脚本示例看个例子吧：#! bin shcd ~mkdir shell_tutcd shell_tutfor ((i=0; i<10; i++)); do touch test_$i.txt...
什么是Shell脚本
示例
看个例子吧：
#!/bin/sh
cd ~
mkdir shell_tut
cd shell_tut
for (...
C# Sortable collection which allows duplicate keys
...Format("{0}:{1}", tuple.Item1,tuple.Item2));
}
int expected_first = 1;
int expected_last = 3;
int first = list.First().Item1; //requires using System.Linq
int last = list.Last().Item1; //requires using System.Linq
Assert.AreEqual(expected_first, fi...
What are some (concrete) use-cases for metaclasses?
...ate methods, than to do something like:
class PlottingInteractive:
add_slice = wrap_pylab_newplot(add_slice)
This method doesn't keep up with API changes and so on, but one that iterates over the class attributes in __init__ before re-setting the class attributes is more efficient and keeps t...