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Grid of responsive squares

... you can code : HTML : <div></div> CSS div { width: 30%; padding-bottom: 30%; /* = width for a square aspect ratio */ } Here is a simple layout example of 3*3 squares grid using the code above. With this technique, you can make any other aspect ratio, here is a table giv...
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Bitwise operation and usage

...bit at a time. AND is 1 only if both of its inputs are 1, otherwise it's 0. OR is 1 if one or both of its inputs are 1, otherwise it's 0. XOR is 1 only if exactly one of its inputs are 1, otherwise it's 0. NOT is 1 only if its input is 0, otherwise it's 0. These can often be best shown as truth ...
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Multiple aggregations of the same column using pandas GroupBy.agg()

... You can simply pass the functions as a list: In [20]: df.groupby("dummy").agg({"returns": [np.mean, np.sum]}) Out[20]: mean sum dummy 1 0.036901 0.369012 or as a dictionary: In [21]: df.groupby('dummy').agg({'returns': ...
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Grep characters before and after match?

... characters after $> echo "some123_string_and_another" | grep -o -P '.{0,3}string.{0,4}' 23_string_and share | improve this answer | follow | ...
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How to use hex color values

...f, green ff and blue ff. You can write hexadecimal notation in Swift using 0x prefix, e.g 0xFF To simplify the conversion, let's create an initializer that takes integer (0 - 255) values: extension UIColor { convenience init(red: Int, green: Int, blue: Int) { assert(red >= 0 &&amp...
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How to validate an e-mail address in swift?

...ValidEmail(_ email: String) -> Bool { let emailRegEx = "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,64}" let emailPred = NSPredicate(format:"SELF MATCHES %@", emailRegEx) return emailPred.evaluate(with: email) } for versions of Swift earlier than 3.0: func isValidEmail(e...
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How do you convert epoch time in C#?

...ou convert Unix epoch time into real time in C#? (Epoch beginning 1/1/1970) 14 Answers ...
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Odd behavior when Java converts int to byte?

...mber is the positive version of that number For example: 11111111 goes to 00000001 = -1. This is what Java will display as the value. What you probably want to do is know the unsigned value of the byte. You can accomplish this with a bitmask that deletes everything but the least significant 8 bit...
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Generate array of all letters and digits

...g ruby, is it possible to make an array of each letter in the alphabet and 0-9 easily? 7 Answers ...
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Fastest way to check if string contains only digits

...tsOnly(string str) { foreach (char c in str) { if (c < '0' || c > '9') return false; } return true; } Will probably be the fastest way to do it. share | ...