大约有 30,000 项符合查询结果(耗时:0.0449秒) [XML]

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How can the Euclidean distance be calculated with NumPy?

...er too much if you use sqrt-sum with axis=0, linalg.norm with axis=0, or a_min_b = a - b numpy.sqrt(numpy.einsum('ij,ij->j', a_min_b, a_min_b)) which is, by a slight margin, the fastest variant. (That actually holds true for just one row as well.) The variants where you sum up over the second...
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How to write an inline IF statement in JavaScript?

...developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/Conditional_Operator share | improve this answer | follow | ...
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How can I get the count of milliseconds since midnight for the current?

... // Get current moment in UTC, then… .get( ChronoField.MILLI_OF_SECOND ) // interrogate a `TemporalField`. 2017-04-25T03:01:14.113Z → 113 Get the fractional second in nanoseconds (billions). Divide by a thousand to truncate to milliseconds (thousands). See this code run l...
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Invalid argument supplied for foreach()

...s to be the most clean - not sure if it's the most efficient, mind! if (is_array($values) || is_object($values)) { foreach ($values as $value) { ... } } The reason for my preference is it doesn't allocate an empty array when you've got nothing to begin with anyway. ...
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Swift - encode URL

... it will encode some characters that do not need to be encoded (like -, ., _ or ~ -– see 2.3. Unreserved characters in RFC 3986). I find using .alphanumerics simpler than constructing a custom character set and do not mind some additional characters to be encoded. If that bothers you, construct a ...
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How do I see what character set a MySQL database / table / column is?

...'d do it - For Schemas (or Databases - they are synonyms): SELECT default_character_set_name FROM information_schema.SCHEMATA WHERE schema_name = "schemaname"; For Tables: SELECT CCSA.character_set_name FROM information_schema.`TABLES` T, information_schema.`COLLATION_CHARACTER_SET_APPL...
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PHP array delete by value (not key)

... Using array_search() and unset, try the following: if (($key = array_search($del_val, $messages)) !== false) { unset($messages[$key]); } array_search() returns the key of the element it finds, which can be used to remove that ele...
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String comparison using '==' vs. 'strcmp()'

...tring2 sorts before string1 or 0 if they are the same. For example $string_first = "aabo"; $string_second = "aaao"; echo $n = strcmp($string_first,$string_second); will return greater than zero, as aaao is sorting before aabo. – HTML Man Aug 16 '13 at 18:00 ...
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How to find out the MySQL root password

...sword. On ubuntu I did the following: sudo service mysql stop sudo mysqld_safe --skip-grant-tables --skip-syslog --skip-networking Then run mysql in a new terminal: mysql -u root And run the following queries to change the password: UPDATE mysql.user SET authentication_string=PASSWORD('passw...
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How to print out more than 20 items (documents) in MongoDB's shell?

...h(function(f){print(tojson(f, '', true));}); which would return only the _id and name field from foo. share | improve this answer | follow | ...