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How do I get the row count of a pandas DataFrame?
... answered Apr 11 '13 at 8:24
rootroot
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SQlite Getting nearest locations (with latitude and longitude)
... do the full haversine just for a sort order and there's no need to square root the results therefore SQLite can handle the calculation.
EDIT:
This answer is still receiving love. It works fine in most cases but if you need a little more accuracy, please check out the answer by @Teasel below which...
Increment a database field by 1
With MySQL, if I have a field, of say logins, how would I go about updating that field by 1 within a sql command?
5 Answers...
Why does sudo change the PATH?
...d env_check
lists are displayed when sudo is run by root with the
-V option. If sudo was compiled with the SECURE_PATH
option, its value will be used for the PATH environment
variable. This flag is on by de...
How can I add reflection to a C++ application?
...ioned below) adds reflection to C++ without slowing down existing code at: root.cern.ch/drupal/content/reflex
– Joseph Lisee
May 4 '11 at 19:37
6
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Defining private module functions in python
...ou can add an inner function:
def public(self, args):
def private(self.root, data):
if (self.root != None):
pass #do something with data
Something like that if you really need that level of privacy.
sh...
How to test an SQL Update statement before running it?
...What about Transactions? They have the ROLLBACK-Feature.
@see https://dev.mysql.com/doc/refman/5.0/en/commit.html
For example:
START TRANSACTION;
SELECT * FROM nicetable WHERE somthing=1;
UPDATE nicetable SET nicefield='VALUE' WHERE somthing=1;
SELECT * FROM nicetable WHERE somthing=1; #check
CO...
How do I select an entire row which has the largest ID in the table?
...show profiles and it appears our solutions have the same performance using MySQL. For my own knowledge, do you know what DBMS has poorer performance for subselects?
– unutbu
Feb 7 '14 at 20:08
...
boost多索引容器multi_index_container实战 - C/C++ - 清泛网 - 专注C/C++及内核技术
...些知识有过了解
什么是多索引容器？为什么要使用它？如何使用？
接下来一一回答以上的问题。
想必大家在实际开发中一定多多少少会遇到以下的问题，我需要创建一个map，并且需要两种方式去索引，比如：创建一个<学号,...
How to stop /#/ in browser with react-router?
...nged a great deal and it is required is to use BrowserRouter as the router root tag.
import BrowserRouter from 'react-router/BrowserRouter'
ReactDOM.render ((
<BrowserRouter>
...
<BrowserRouter>
), document.body);
Source React Router Version 4 Docs
...