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How to use PyCharm to debug Scrapy projects
... a virtualenv with Python 3.5.0 and setting the "script" parameter to /path_to_project_env/env/bin/scrapy solved the issue for me.
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What is Hindley-Milner?
...nsion called the value restriction.)
Many other minor languages and tools based on typed functional languages use Hindley-Milner.
Hindley-Milner is a restriction of System F, which allows more types but which requires annotations by the programmer.
...
Difference between author and committer in Git?
...duces two commits per pull request, and keeps a fork in the git history.
rebase on top of master
GitHub also hacks the commits to set committer == whoever pressed the merge button. This is not mandatory, and not even done by default locally by git rebase, but it gives accountability to the project ...
warning: implicit declaration of function
...s to declare function prototype in header.
Example
main.h
#ifndef MAIN_H
#define MAIN_H
int some_main(const char *name);
#endif
main.c
#include "main.h"
int main()
{
some_main("Hello, World\n");
}
int some_main(const char *name)
{
printf("%s", name);
}
Alternative with one file...
How to avoid annoying error “declared and not used”
..., if you really want to skip this error, you can use the blank identifier (_) :
package main
import (
"fmt" // imported and not used: "fmt"
)
func main() {
i := 1 // i declared and not used
}
becomes
package main
import (
_ "fmt" // no more error
)
func main() {
i := 1 // no ...
How to get datetime in JavaScript?
...
function pad_2(number)
{
return (number < 10 ? '0' : '') + number;
}
function hours(date)
{
var hours = date.getHours();
if(hours > 12)
return hours - 12; // Substract 12 hours when 13:00 and more
return h...
Performance of Find() vs. FirstOrDefault() [duplicate]
...ject an anonmyous data item just for compilation
List<\u003C\u003Ef__AnonymousType0<string>> source = Enumerable.ToList(Enumerable.Select(Enumerable.Range(0, 1000000), i =>
{
var local_0 = new
{
Name = Guid.NewGuid().ToString()
};
return local_...
Dictionaries and default values
...collections import defaultdict
a = defaultdict(lambda: "default", key="some_value")
a["blabla"] => "default"
a["key"] => "some_value"
You can pass any ordinary function instead of lambda:
from collections import defaultdict
def a():
return 4
b = defaultdict(a, key="some_value")
b['absent...
Downloading a file from spring controllers
...ly supporting a dozen types of resources. We might support more file types based on what users want to upload in that case we might end up with so many end points essentially doing the same thing. IMHO there has to be only one download end point and it handles multitude of file types. @Francis
...
Does Python support short-circuiting?
...ent, but you could also state things very succinctly:
In [171]: name = raw_input('Enter Name: ') or '<Unkown>'
Enter Name:
In [172]: name
Out[172]: '<Unkown>'
In other words, if the return value from raw_input is true (not an empty string), it is assigned to name (nothing changes); ...