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Why do some C# lambda expressions compile to static methods?
...tion<string> withClosure = s => Console.WriteLine("My name is {0} and I am {1} years old", s, age);
Action<string> withoutClosure = s => Console.WriteLine("My name is {0}", s);
Console.WriteLine(withClosure.Method.IsStatic);
Console.WriteLine(withoutClosure.Method.IsStatic);
This...
Get the real width and height of an image with JavaScript? (in Safari/Chrome)
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Webkit browsers set the height and width property after the image is loaded. Instead of using timeouts, I'd recommend using an image's onload event. Here's a quick example:
var img = $("img")[0]; // Get my img elem
var pic_real_width, pic_real_height;
$...
What is the meaning of the term arena in relation to memory?
... arena , but never defines it. I've searched for the meaning of the word and how it relates to memory, and found nothing. Here are a few contexts in which the author uses the term:
...
Configure Flask dev server to be visible across the network
... To set to a specific ip app.run(host="192.168.1.7",port=5010) handy if your pc has a few ip's
– lxx
Jan 2 '15 at 3:29
2
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How is the AND/OR operator represented as in Regular Expressions?
...ou want to build a the regex dynamically to contain other words than part1 and part2, and that you want order not to matter. If so you can use something like this:
((^|, )(part1|part2|part3))+$
Positive matches:
part1
part2, part1
part1, part2, part3
Negative matches:
part1, //with ...
MongoDB: Combine data from multiple collections into one..how?
...you can use as an _id.
For example, let's say you have a users collection and a comments collection and you want to have a new collection that has some user demographic info for each comment.
Let's say the users collection has the following fields:
_id
firstName
lastName
country
gender
age
And...
Merge up to a specific commit
...med newbranch from the master branch in git. Now I have done some work and want to merge newbranch to master ; however, I have made some extra changes to newbranch and I want to merge newbranch up to the fourth-from-the-last commit to master .
...
What's the difference between io.sockets.emit and broadcast?
What's the difference between io.sockets.emit and socket.broadcast.emit? Is it only that broadcast emits to everyone BUT the socket that sends it?
...
What is the difference between origin and upstream on GitHub?
What is the difference between origin and upstream on GitHub ?
1 Answer
1
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How do I update an entity using spring-data-jpa?
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Identity of entities is defined by their primary keys. Since firstname and lastname are not parts of the primary key, you cannot tell JPA to treat Users with the same firstnames and lastnames as equal if they have different userIds.
So, if you want to update a User identified by its firstname a...