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Fastest way to check if a string matches a regexp in ruby?
...y
require 'benchmark'
str = "aacaabc"
re = Regexp.new('a+b').freeze
N = 4_000_000
Benchmark.bm do |b|
b.report("str.match re\t") { N.times { str.match re } }
b.report("str =~ re\t") { N.times { str =~ re } }
b.report("str[re] \t") { N.times { str[re] } }
b.report("re =~ str...
Convert an NSURL to an NSString
...[myURL absoluteString]; But I had met this error and xcode was crashed. -[__NSCFString absoluteString]: unrecognized selector sent to instance 0x791a18e0
– Võ Mai Trinh
Jun 22 '15 at 9:39
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How does Rails keep track of which migrations have run for a database?
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Rails creates a table in your database called schema_migrations to keep track of which migrations have run.
The table contains a single column, version. When Rails runs a migration, it takes the leading digits in the migration's file name and inserts a row for that "version",...
Android file chooser [closed]
...tent in an Intent.createChooser() like this:
private static final int FILE_SELECT_CODE = 0;
private void showFileChooser() {
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("*/*");
intent.addCategory(Intent.CATEGORY_OPENABLE);
try {
startActivityFor...
How to use “raise” keyword in Python [duplicate]
...dler, so that it can be handled further up the call stack.
try:
generate_exception()
except SomeException as e:
if not can_handle(e):
raise
handle_exception(e)
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How do I know which version of Javascript I'm using?
...eaten-path one is IE9 - it implements ECMAScript 5, but doesn't implement all the features of JavaScript 1.8.5 (not sure what they're calling this version of JScript, engine codenamed Chakra, yet).
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How are echo and print different in PHP? [duplicate]
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From:
http://web.archive.org/web/20090221144611/http://faqts.com/knowledge_base/view.phtml/aid/1/fid/40
Speed. There is a difference between the two, but speed-wise it
should be irrelevant which one you use. echo is marginally faster
since it doesn't set a return value if you really want to ge...
How to use/install gcc on Mac OS X 10.8 / Xcode 4.4
... Apple LLVM version 6.0 (clang-600.0.51) (based on LLVM 3.5svn) Target: x86_64-apple-darwin14.0.0 Thread model: posix So am I using gcc?
– Thomas
Dec 14 '14 at 16:11
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PostgreSQL naming conventions
.... Postgresql treats identifiers case insensitively when not quoted (it actually folds them to lowercase internally), and case sensitively when quoted; many people are not aware of this idiosyncrasy. Using always lowercase you are safe. Anyway, it's acceptable to use camelCase or PascalCase (or UPPER...
Checking for an empty field with MySQL
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If you want to find all records that are not NULL, and either empty or have any number of spaces, this will work:
LIKE '%\ '
Make sure that there's a space after the backslash. More info here: http://dev.mysql.com/doc/refman/5.0/en/string-com...