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Object reference not set to an instance of an object.Why doesn't .NET show which object is `null`?
...ull
IL_0002: stloc.0 // s
IL_0003: ldloc.0 // s
IL_0004: callvirt System.String.get_Length
IL_0009: call System.Console.WriteLine
It is the callvirt opcode that throws the NullReferenceException and it does that when the first argument on the evaluation stack is a null ...
How to check if a python module exists without importing it
...ING
When trying to find a submodule, it will import the parent module (for all of the above methods)!
food/
|- __init__.py
|- eggs.py
## __init__.py
print("module food loaded")
## eggs.py
print("module eggs")
were you then to run
>>> import importlib
>>> spam_spec = importli...
Compare two DataFrames and output their differences side-by-side
...original question
The first step is to concatenate the DataFrames horizontally with the concat function and distinguish each frame with the keys parameter:
df_all = pd.concat([df.set_index('id'), df2.set_index('id')],
axis='columns', keys=['First', 'Second'])
df_all
It's pr...
From an array of objects, extract value of a property as array
... it uses a syntax that wasn't available at the time you asked the question and isn't even supported in some browsers. I'd also note that this answer is a direct copy of comments that were made on the originally accepted answer nearly a year before this answer was posted.
– Aln...
Javascript replace with reference to matched group?
...hello _there_ . I'd like to replace the two underscores with <div> and </div> respectively, using JavaScript . The output would (therefore) look like hello <div>there</div> . The string might contain multiple pairs of underscores.
...
Chrome sendrequest error: TypeError: Converting circular structure to JSON
...s. document has a reference to the DOM tree at least through document.body and document.body.ownerDocument refers back to document again, which is only one of multiple circular references in the DOM tree.
share
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Android Notification Sound
...n Codeding
String en_alert, th_alert, en_title, th_title, id;
int noti_all, noti_1, noti_2, noti_3, noti_4 = 0, Langage;
class method
Intent intent = new Intent(context, ReserveStatusActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
Notificati...
Get element inside element by class and ID - JavaScript
...er than worrying about browser compatibility yourself (let someone else do all the work). If you want just a library to do that, then Sizzle will work great. In Sizzle, this would be be done like this:
Sizzle("#foo .bar")[0].innerHTML = "Goodbye world!";
jQuery has the Sizzle library built-in...
Can I use a binary literal in C or C++?
... 2 formatting with STL streams (since setbase will only honour bases 8, 10 and 16), but you can use either a std::string version of itoa, or (the more concise, yet marginally less efficient) std::bitset.
#include <boost/utility/binary.hpp>
#include <stdio.h>
#include <stdlib.h>
#i...
Attach parameter to button.addTarget action in Swift
...
I appreciate everyone saying use tags, but really you need to extend the UIButton class and simply add the object there..
Tags are a hopeless way round this. Extend the UIButton like this (in Swift 4)
import UIKit
class PassableUIButton: UIButton{
var params: Dic...