string

what’s the use of string.Clone()?

This is useful since string implements ICloneable, so you can create a copy of clones for a collection of ICloneable items. This is boring when the collection is of strings only, but it’s useful when the collection contains multiple types that implement ICloneable. As for copying a single string it has no use, since it … Read more

pandas combine two strings ignore nan values

Call fillna and pass an empty str as the fill value and then sum with param axis=1: In [3]: df = pd.DataFrame({‘a’:[‘asd’,np.NaN,’asdsa’], ‘b’:[‘asdas’,’asdas’,np.NaN]}) df Out[3]: a b 0 asd asdas 1 NaN asdas 2 asdsa NaN In [7]: df[‘a+b’] = df.fillna(”).sum(axis=1) df Out[7]: a b a+b 0 asd asdas asdasdas 1 NaN asdas asdas 2 … Read more

Regex to match an IP address [closed]

Don’t use a regex when you don’t need to 🙂 $valid = filter_var($string, FILTER_VALIDATE_IP); Though if you really do want a regex… $valid = preg_match(‘/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\z/’, $string); The regex however will only validate the format, the max for any octet is the max for an unsigned byte, or 255. This is why IPv6 is necessary – … Read more

How do I include the string header?

You want to include <string> and use std::string: #include <string> #include <iostream> int main() { std::string s = “a string”; std::cout << s << std::endl; } But what you really need to do is get an introductory level book. You aren’t going to learn properly any other way, certainly not scrapping for information online.