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Test if a variable is a list or tuple
... excludes custom sequences, iterators, and other things that you might actually need. However, sometimes you need to behave differently if someone, for instance, passes a string. My preference there would be to explicitly check for str or unicode like so:
import types
isinstance(var, types.String...
How to Rotate a UIImage 90 degrees?
...nt to use a CGAffineTransform . I want the pixels of the UIImage to actually shift position. I am using a block of code (shown below) originally intended to resize a UIImage to do this. I set a target size as the current size of the UIImage but I get an error:
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How to track down a “double free or corruption” error
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If you're using glibc, you can set the MALLOC_CHECK_ environment variable to 2, this will cause glibc to use an error tolerant version of malloc, which will cause your program to abort at the point where the double free is done.
You can set this from gdb by using ...
What is the best collation to use for MySQL with PHP? [closed]
...site where you aren't 100% sure of what will be entered? I understand that all the encodings should be the same, such as MySQL, Apache, the HTML and anything inside PHP.
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What's the difference between process.cwd() vs __dirname?
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Does this mean that process.cwd() is synonym to . for all cases except for require()?
– Alexander Gonchiy
Aug 29 '15 at 9:44
11
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How to take the first N items from a generator or list in Python? [duplicate]
...imple syntax: array[start:stop:step]
You can omit any parameter. These are all valid: array[start:], array[:stop], array[::step]
Slicing a generator
import itertools
top5 = itertools.islice(my_list, 5) # grab the first five elements
You can't slice a generator directly in Python. itertools.i...
Rails: Missing host to link to! Please provide :host parameter or set default_url_options[:host]
...default_url_options = { :host => "yourhost" }
That way, it can work in all environments and could be different from environment to environment. For example:
development.rb
config.action_mailer.default_url_options = { :host => "dev.yourhost.com" }
test.rb
config.action_mailer.default_url_...
How to remove non-alphanumeric characters?
I need to remove all characters from a string which aren't in a-z A-Z 0-9 set or are not spaces.
9 Answers
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How to rename with prefix/suffix?
...available and you have to rename more than one file, shell scripting can really be short and simple for this. For example, to rename all *.jpg to prefix_*.jpg in the current directory:
for filename in *.jpg; do mv "$filename" "prefix_$filename"; done;
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What is the correct way to represent null XML elements?
...l is the correct way to represent a value such that:
When the DOM Level 2 call getElementValue() is issued, the NULL value is returned.
xsi:nil is also used to indicate a valid element with no content even if that elements content type normally doesn't allow empty elements.
If an empty tag is used,...