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How to declare a type as nullable in TypeScript?
...r undefined.
You can make the field optional which is different from nullable.
interface Employee1 {
name: string;
salary: number;
}
var a: Employee1 = { name: 'Bob', salary: 40000 }; // OK
var b: Employee1 = { name: 'Bob' }; // Not OK, you must have 'salary'
var c: Employee1 = { name: 'B...
How to set environment variables in Python?
...
Environment variables must be strings, so use
os.environ["DEBUSSY"] = "1"
to set the variable DEBUSSY to the string 1.
To access this variable later, simply use:
print(os.environ["DEBUSSY"])
Child processes automatically inherit the environment variable...
What is the exact difference between currentTarget property and target property in javascript
Can anyone please tell me the exact difference between currentTarget and target property in Javascript events with example and which property is used in which scenario?
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how to check the dtype of a column in python pandas
...treat numeric columns and string columns. What I am doing now is really dumb:
6 Answers
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What does the * * CSS selector do?
...other time you put two selectors one after another (for example li a), you get the descendant combinator. So * * is any element that is a descendant of any other element — in other words, any element that isn't the root element of the whole document.
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std::auto_ptr to std::unique_ptr
With the new standard coming (and parts already available in some compilers), the new type std::unique_ptr is supposed to be a replacement for std::auto_ptr .
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socket.shutdown vs socket.close
I recently saw a bit of code that looked like this (with sock being a socket object of course):
7 Answers
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How do I find which transaction is causing a “Waiting for table metadata lock” state?
I am trying to perform some DDL on a table and SHOW PROCESSLIST results in a " Waiting for table metadata lock " message.
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Execute SQLite script
I start up sqlite3 version 3.7.7, unix 11.4.2 using this command:
5 Answers
5
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ruby convert array into function arguments
... the * (or "splat") operator:
a = [0, 1, 2, 3, 4] # => [0, 1, 2, 3, 4]
b = [2, 3] # => [2, 3]
a.slice(*b) # => [2, 3, 4]
Reference:
Array to Arguments Conversion
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