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Evaluating a mathematical expression in a string
This returns the following error:
11 Answers
11
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What is the difference between persist() and merge() in JPA and Hibernate?
... it
becomes managed. The entity X will be
entered into the database at or before
transaction commit or as a result of
the flush operation.
If X is a
preexisting managed entity, it is
ignored by the persist operation.
However, the persist operation is
cascaded to entities referenced...
What data type to use for hashed password field and what length?
I'm not sure how password hashing works (will be implementing it later), but need to create database schema now.
10 Answers...
How to use SVN, Branch? Tag? Trunk?
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The subversion book is an excellent source of information on strategies for laying out your repository, branching and tagging.
See also:
Do you continue development in a branch or in the trunk
Branching strategies
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What is the difference between join and merge in Pandas?
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I always use join on indices:
import pandas as pd
left = pd.DataFrame({'key': ['foo', 'bar'], 'val': [1, 2]}).set_index('key')
right = pd.DataFrame({'key': ['foo', 'bar'], 'val': [4, 5]}).set_index('key')
left.join(right, lsuffix='_l', rsuffix='_r')
va...
Scatter plot and Color mapping in Python
I have a range of points x and y stored in numpy arrays.
Those represent x(t) and y(t) where t=0...T-1
3 Answers
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How to identify server IP address in PHP
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Like this for the server ip:
$_SERVER['SERVER_ADDR'];
and this for the port
$_SERVER['SERVER_PORT'];
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Is there a standard function to check for null, undefined, or blank variables in JavaScript?
...t checks that a variable has a value and ensures that it's not undefined or null ? I've got this code, but I'm not sure if it covers all cases:
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How do I capture response of form.submit
...ou won't be able to do this easily with plain javascript. When you post a form, the form inputs are sent to the server and your page is refreshed - the data is handled on the server side. That is, the submit() function doesn't actually return anything, it just sends the form data to the server.
If ...
How do I pass a unique_ptr argument to a constructor or a function?
...d I don't know very well how to handle unique_ptr parameters in constructors or functions. Consider this class referencing itself:
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