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How to check if a json key exists?
...
just before read key check it like before read
JSONObject json_obj=new JSONObject(yourjsonstr);
if(!json_obj.isNull("club"))
{
//it's contain value to be read operation
}
else
{
//it's not contain key club or isnull so do this opera...
What part of Hindley-Milner do you not understand?
...s that the environment Γ includes the fact that x has type σ.
⊢ can be read as proves or determines. Γ ⊢ x : σ means that the environment Γ determines that x has type σ.
, is a way of including specific additional assumptions into an environment Γ.
Therefore, Γ, x : τ ⊢ e : τ' means ...
Haskell composition (.) vs F#'s pipe forward operator (|>)
...e appears on the left (see here).
(Personally, I find points-free style unreadable, but I suppose every new/different thing seems unreadable until you become accustomed to it.)
I think both are potentially viable in either language, and history/culture/accident may define why each community settle...
Differences between Emacs and Vim
...better than most text editors. It recognizes that most of the time you are reading/editing not typing and makes that portion faster. You don't suffer from emacs pinkie. It's not so infuriating. It's easier to learn.
Even though I use Emacs all day every day (and love it) unless you intend to spend...
How to deal with SettingWithCopyWarning in Pandas?
...for false positives is addressed in the docs on indexing, if you'd like to read further. You can safely disable this new warning with the following assignment.
import pandas as pd
pd.options.mode.chained_assignment = None # default='warn'
...
How do you get a string from a MemoryStream?
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This sample shows how to read and write a string to a MemoryStream.
Imports System.IO
Module Module1
Sub Main()
' We don't need to dispose any of the MemoryStream
' because it is a managed object. However, just for
' good practic...
Why does C++ need a separate header file?
...having to include header files, but having to explicitly check if it has already been included.
13 Answers
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Can (domain name) subdomains have an underscore “_” in it?
...ginal DNS specification, RFC 1034, section 3.5
"Preferred name syntax" but read it carefully.
Domains with underscores are very common in the wild. Check _jabber._tcp.gmail.com or _sip._udp.apnic.net.
Other RFC mentioned here deal with different things. The original
question was for domain names. ...
Import CSV file to strongly typed data structure in .Net [closed]
...upported, most of which cannot be said for FileHelpers.
See also: How to: Read From Comma-Delimited Text Files in Visual Basic for a VB code example.
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What is REST? Slightly confused [closed]
...ures" (available online from the University of California, Irvine).
First read Ryan Tomayko's post How I explained REST to my wife; it's a great starting point. Then read Fielding's actual dissertation. It's not that advanced, nor is it long (six chapters, 180 pages)! (I know you kids in school li...