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How to get the last N rows of a pandas DataFrame?
I have pandas dataframe df1 and df2 (df1 is vanila dataframe, df2 is indexed by 'STK_ID' & 'RPT_Date') :
3 Answers
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How to set the prototype of a JavaScript object that has already been instantiated?
...e I have an object foo in my JavaScript code. foo is a complex object and it is generated somewhere else. How can I change the prototype of the foo object?
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What can be the reasons of connection refused errors?
... its backlog of pending connections is full.
A firewall between the client and server is blocking access (also check local firewalls).
After checking for firewalls and that the port is open, use telnet to connect to the ip/port to test connectivity. This removes any potential issues from your appl...
What does the “expand” option do in grunt-contrib-copy? The examples all use it but the docs say not
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Expand lets you specify whether you want to create the destination path in full (e.g: /path/missing1/missing2), or only create the last directory when its parent exists (/path/existing/missing).
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string c_str() vs. data()
I have read several places that the difference between c_str() and data() (in STL and other implementations) is that c_str() is always null terminated while data() is not.
As far as I have seen in actual implementations, they either do the same or data() calls c_str() .
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Declaring functions in JavaScript [duplicate]
...cally this syntax may mean the same for declaring functions both ways
(I stand incorrect on my last statement. I read up on a diff post why they are technically diff and I'll add in the end, why)
; but the way they play a role in evolving patterns is massive. I would highly recommend "Javascript: Th...
How can I get the current PowerShell executing file?
...for PowerShell 5:
If you're only using PowerShell 3 or higher, use $PSCommandPath
If want compatibility with older versions, insert the shim:
if ($PSCommandPath -eq $null) { function GetPSCommandPath() { return $MyInvocation.PSCommandPath; } $PSCommandPath = GetPSCommandPath; }
This adds $PSComman...
How to find all combinations of coins when given some dollar value
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I looked into this once a long time ago, and you can read my little write-up on it. Here’s the Mathematica source.
By using generating functions, you can get a closed-form constant-time solution to the problem. Graham, Knuth, and Patashnik’s Concrete Mathematic...
Java executors: how to be notified, without blocking, when a task completes?
... of the task.
You could even write a general wrapper for Runnable tasks, and submit these to ExecutorService. Or, see below for a mechanism built into Java 8.
class CallbackTask implements Runnable {
private final Runnable task;
private final Callback callback;
CallbackTask(Runnable task...
Java: What is the difference between and ?
I am unable to understand the following text... Does it mean that <clinit> is for empty constructors? Why is important to have two different versions?
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