a notation for representing fixed values in source code
External links
- Wikipedia: Literal (computer programming)
Questions tagged [literals]
1554 questions
795
votes
5 answers
Why is [] faster than list()?
I recently compared the processing speeds of [] and list() and was surprised to discover that [] runs more than three times faster than list(). I ran the same test with {} and dict() and the results were practically identical: [] and {} both took…
Augusta
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594
votes
7 answers
Empty set literal?
[] = empty list
() = empty tuple
{} = empty dict
Is there a similar notation for an empty set?
Or do I have to write set()?
Johan Råde
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583
votes
6 answers
Can I escape a double quote in a verbatim string literal?
In a verbatim string literal (@"foo") in C#, backslashes aren't treated as escapes, so doing \" to get a double quote doesn't work. Is there any way to get a double quote in a verbatim string literal?
This understandably doesn't work:
string foo =…
kdt
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442
votes
5 answers
What does the M stand for in C# Decimal literal notation?
In order to work with decimal data types, I have to do this with variable initialization:
decimal aValue = 50.0M;
What does the M part stand for?
coson
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397
votes
8 answers
How do you express binary literals in Python?
How do you express an integer as a binary number with Python literals?
I was easily able to find the answer for hex:
>>> 0x12AF
4783
>>> 0x100
256
and octal:
>>> 01267
695
>>> 0100
64
How do you use literals to express binary in Python?
Summary…
Justin Standard
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332
votes
10 answers
Why does instanceof return false for some literals?
"foo" instanceof String //=> false
"foo" instanceof Object //=> false
true instanceof Boolean //=> false
true instanceof Object //=> false
false instanceof Boolean //=> false
false instanceof Object //=> false
12.21 instanceof Number //=>…
Jonathan Lonowski
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296
votes
3 answers
What is the >>>= operator in C?
Given by a colleague as a puzzle, I cannot figure out how this C program actually compiles and runs. What is this >>>= operator and the strange 1P1 literal? I have tested in Clang and GCC. There are no warnings and the output is "???"
#include…
CustomCalc
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278
votes
6 answers
How do you specify a byte literal in Java?
If I have a method
void f(byte b);
how can I call it with a numeric argument without casting?
f(0);
gives an error.
Charbel
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273
votes
5 answers
C# short/long/int literal format?
In C/C#/etc. you can tell the compiler that a literal number is not what it appears to be (ie., float instead of double, unsigned long instead of int):
var d = 1.0; // double
var f = 1.0f; // float
var u = 1UL; // unsigned long
etc.
Could someone…
3Dave
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262
votes
9 answers
Java: how do I get a class literal from a generic type?
Typically, I've seen people use the class literal like this:
Class cls = Foo.class;
But what if the type is generic, e.g. List? This works fine, but has a warning since List should be parameterized:
Class
- cls = List.class
So why not add…
Tom
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258
votes
14 answers
Why can't Python's raw string literals end with a single backslash?
Technically, any odd number of backslashes, as described in the documentation.
>>> r'\'
File "", line 1
r'\'
^
SyntaxError: EOL while scanning string literal
>>> r'\\'
'\\\\'
>>> r'\\\'
File "", line 1
r'\\\'
…
cdleary
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252
votes
4 answers
(-2147483648> 0) returns true in C++?
-2147483648 is the smallest integer for integer type with 32 bits, but it seems that it will overflow in the if(...) sentence:
if (-2147483648 > 0)
std::cout << "true";
else
std::cout << "false";
This will print true in my testing. However,…
benyl
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233
votes
4 answers
Literal notation for Dictionary in C#?
I currently have a WebSocket between JavaScript and a server programmed in C#. In JavaScript, I can pass data easily using an associative array:
var data = {'test': 'val',
'test2': 'val2'};
To represent this data object on the server…
pimvdb
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193
votes
4 answers
How do I do a literal *int64 in Go?
I have a struct type with a *int64 field.
type SomeType struct {
SomeField *int64
}
At some point in my code, I want to declare a literal of this (say, when I know said value should be 0, or pointing to a 0, you know what I mean)
instance :=…
ThisGuy
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169
votes
2 answers
What does preceding a string literal with "r" mean?
I first saw it used in building regular expressions across multiple lines as a method argument to re.compile(), so I assumed that r stands for RegEx.
For example:
regex = re.compile(
r'^[A-Z]'
r'[A-Z0-9-]'
r'[A-Z]$', re.IGNORECASE
)
So…
Nikki Erwin Ramirez
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