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How to quickly check if folder is empty (.NET)?
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There is a new feature in Directory and DirectoryInfo in .NET 4 that allows them to return an IEnumerable instead of an array, and start returning results before reading all the directory contents.
What's New in the BCL in .NET 4 Beta 1
Directory.EnumerateFileSystemEntries method overloads
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How to permanently set $PATH on Linux/Unix? [closed]
...t. The actual solution depends on the purpose.
The variable values are usually stored in either a list of assignments or a shell script that is run at the start of the system or user session. In case of the shell script you must use a specific shell syntax and export or set commands.
System wide
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When saving, how can you check if a field has changed?
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Essentially, you want to override the __init__ method of models.Model so that you keep a copy of the original value. This makes it so that you don't have to do another DB lookup (which is always a good thing).
class Person(models.Model):
name = models.CharF...
get list from pandas dataframe column
...rame columns are Pandas Series when you pull them out, which you can then call x.tolist() on to turn them into a Python list. Alternatively you cast it with list(x).
import pandas as pd
data_dict = {'one': pd.Series([1, 2, 3], index=['a', 'b', 'c']),
'two': pd.Series([1, 2, 3, 4], inde...
[完整源码实例] 修改 CListCtrl 的标题栏字体颜色；重绘 CListCtrl 标题栏 ...
... 0, // cStrikeOut
ANSI_CHARSET, // nCharSet
OUT_DEFAULT_PRECIS, // nOutPrecision
CLIP_DEFAULT_PRECIS, // nClipPrecision
DEFAULT_QUALI...
Numpy first occurrence of value greater than existing value
... about why it gives the correct result despite the original intent not actually seeking a maximum, not why it is faster as I cannot claim to understand the inner details of argmax.
– askewchan
Oct 8 '14 at 14:24
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C++ Dynamic Shared Library on Linux
...were for a plugin system, you would use MyClass as a base class and define all the required functions virtual. The plugin author would then derive from MyClass, override the virtuals and implement create_object and destroy_object. Your main application would not need to be changed in any way.
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How do I speed up the gwt compiler?
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Let's start with the uncomfortable truth: GWT compiler performance is really lousy. You can use some hacks here and there, but you're not going to get significantly better performance.
A nice performance hack you can do is to compile for only specific browsers, by inserting the following line in...
Total memory used by Python process?
...os
import psutil
process = psutil.Process(os.getpid())
print(process.memory_info().rss) # in bytes
On my current Python 2.7 install with psutil 5.6.3, the last line should be
print(process.memory_info()[0])
instead (there was a change in the API).
Note: do pip install psutil if it is not in...
Create unique constraint with null columns
...or may not be useful. In extreme situations it might even help to maintain all three indexes (the two partial ones and a total on top).
Aside: I advise not to use mixed case identifiers in PostgreSQL.
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