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if A vs if A is not None:
...back to database stuff. There's a big difference between NULL and an empty string. An empty string typically says "there's a value here, and that value is nothing at all". NULL says "this value hasn't been entered."
In each of those cases, you'd want to use if A is None. You're checking for a speci...
No internet on Android emulator - why and how to fix? [closed]
...y My APN.
Click on APN. Enter www.
Click on Proxy. enter your proxy server IP. you can get it from internet explorers internet options menu.
click on Port. enter port number in my case it was 8080. you can get it from internet explorers internet options menu.
Click on User-name. provide user-name in...
Convert to binary and keep leading zeros in Python
...most compact and direct option.
If you are putting the result in a larger string, use an formatted string literal (3.6+) or use str.format() and put the second argument for the format() function after the colon of the placeholder {:..}:
>>> value = 14
>>> f'The produced output, i...
How to debug an apache virtual host configuration?
... type the following command:
httpd -S
This command will dump out a description of how Apache parsed the configuration file. Careful examination of the IP addresses and server names may help uncover configuration mistakes. (See the docs for the httpd program for other command line options).
...
C++: What is the size of an object of an empty class?
...aligned on a word boundary (such as an integer). For example, if you place char x; int y; inside the class, my GCC clocks it at eight bytes (since the second int must be aligned in that implementation).
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Best way to strip punctuation from a string
...om an efficiency perspective, you're not going to beat
s.translate(None, string.punctuation)
For higher versions of Python use the following code:
s.translate(str.maketrans('', '', string.punctuation))
It's performing raw string operations in C with a lookup table - there's not much that will...
Create an array with same element repeated multiple times
...ate (05/11/2019):
Another way, without using fill or from, that works for string of any length:
Array.apply(null, Array(3)).map(_ => 'abc') // ['abc', 'abc', 'abc']
Same as above answer. Adding for sake of completeness.
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How does this program work?
...oat is converted to double, as the prototype of printf is int printf(const char*, ...), from 6.5.2.2/7,
The ellipsis notation in a function prototype declarator causes argument type conversion to stop after the last declared parameter. The default argument promotions are performed on trailing ar...
Why don't Java's +=, -=, *=, /= compound assignment operators require casting?
...57
or
byte b = 100;
b /= 2.5;
System.out.println(b); // prints 40
or
char ch = '0';
ch *= 1.1;
System.out.println(ch); // prints '4'
or
char ch = 'A';
ch *= 1.5;
System.out.println(ch); // prints 'a'
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How to check if a string contains only digits in Java [duplicate]
In Java for String class there is a method called matches, how to use this method to check if my string is having only digits using regular expression. I tried with below examples, but both of them returned me false as result.
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