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How to check whether a pandas DataFrame is empty?
...[8]: len(df1.columns)
Out[8]: 0
In [9]: len(df2.columns)
Out[9]: 2
Critically, while the second dataframe df2 contains no data, it is not completely empty because it returns the amount of empty columns that persist.
Why it matters
Let's add a new column to these dataframes to understand the implic...
Difference between 'python setup.py install' and 'pip install'
I have an external package I want to install into my python virtualenv from a tar file.
What is the best way to install the package?
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Getting file names without extensions
...NameWithoutExtension - you'll likely do better writing your own code that calls it.
– Rup
Jan 28 '16 at 9:47
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Difference between array_map, array_walk and array_filter
...ray_filter . What I could see from documentation is that you could pass a callback function to perform an action on the supplied array. But I don't seem to find any particular difference between them.
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Why does Apple recommend to use dispatch_once for implementing the singleton pattern under ARC?
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dispatch_once() is absolutely synchronous. Not all GCD methods do things asynchronously (case in point, dispatch_sync() is synchronous). The use of dispatch_once() replaces the following idiom:
+ (MyClass *)sharedInstance {
static MyClass *sharedInstance;
@synchr...
String formatting named parameters?
I know it's a really simple question, but I have no idea how to google it.
6 Answers
6...
Java FileOutputStream Create File if not exists
...condition is redundant. According to JavaDoc, createNewFile() itself atomically checks the existence of the file.
– aztek
Oct 2 '12 at 10:11
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What is event bubbling and capturing?
...utermost element and propagated to the inner elements.
Capturing is also called "trickling", which helps remember the propagation order:
trickle down, bubble up
Back in the old days, Netscape advocated event capturing, while Microsoft promoted event bubbling. Both are part of the W3C Document...
What is the best way to programmatically detect porn images? [closed]
...rm of spam these days. What if I wanted something like akismet to automatically detect porn images on a social networking site which allows users to upload their pics, avatars, etc?
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How can I transform string to UTF-8 in C#?
...hould also write Console.OutputEncoding = System.Text.Encoding.UTF8;!!! Or all utf8 strings will be outputed as gbk...
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