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How can I reverse a NSArray in Objective-C?
...ne. If I see a method that returns an immutable object, I expect it to actually be returning an immutable object. Having it appear to return an immutable object but actual return a mutable object is a dangerous practice to get into.
– Christine
Jul 2 '12 at 22:...
How do I write JSON data to a file?
... codecs.getwriter('utf-8')(f), ensure_ascii=False)
The codecs.getwriter call is redundant in Python 3 but required for Python 2
Readability and size:
The use of ensure_ascii=False gives better readability and smaller size:
>>> json.dumps({'price': '€10'})
'{"price": "\\u20ac10"}'
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Adding :default => true to boolean in existing Rails column
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change_column is a method of ActiveRecord::Migration, so you can't call it like that in the console.
If you want to add a default value for this column, create a new migration:
rails g migration add_default_value_to_show_attribute
Then in the migration created:
# That's the more generic way t...
How to apply a function to two columns of Pandas dataframe
Suppose I have a df which has columns of 'ID', 'col_1', 'col_2' . And I define a function :
12 Answers
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How can one display images side by side in a GitHub README.md?
...refer to specify the image as a percentage of the total width, e.g. width="32%" when aligning 3 images
– Igor Fobia
Jun 26 at 13:42
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What does the “@” symbol do in Powershell?
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PowerShell will actually treat any comma-separated list as an array:
"server1","server2"
So the @ is optional in those cases. However, for associative arrays, the @ is required:
@{"Key"="Value";"Key2"="Value2"}
Officially, @ is the "array ...
#ifdef replacement in the Swift language
... After i set the custom flag -DLOCAL, on my #if LOCAl #else #endif, it falls into the #else section. I duplicated the original target AppTarget and rename it to AppTargetLocal & set its custom flag.
– Perwyl Liu
Jul 20 '16 at 6:48
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How can you profile a Python script?
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Python includes a profiler called cProfile. It not only gives the total running time, but also times each function separately, and tells you how many times each function was called, making it easy to determine where you should make optimizations.
You c...
How to use/install gcc on Mac OS X 10.8 / Xcode 4.4
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answered Jul 29 '12 at 11:32
VolcanicVolcanic
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Which characters are valid/invalid in a JSON key name?
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Not those. Whatever needs escaping in JavaScript generally needs it in JSON. Best to get it from the horse's mouth, though, at json.org. It takes about one minute to read the entire spec end-to-end.
– Marcelo Cantos
Dec 30 '11 at 4:21
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