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137. default value, computed value

VBScript

JScript

Perl

my %counts;
$counts{'foo'} += 1

define a tied hash for computed values and defaults other than zero or empty string

PHP

$counts = array();
$counts['foo'] += 1;

extend ArrayObject for computed values and defaults other than zero or empty string.

Python

from collections import defaultdict

counts = defaultdict(lambda: 0)
counts['foo'] += 1

class Factorial(dict):
  def __missing__(self, k):
    if k > 1:
      return k * self[k-1]
    else:
      return 1

factorial = Factorial()

Ruby

counts = Hash.new(0)
counts['foo'] += 1

factorial = Hash.new do |h,k|
  k > 1 ? k * h[k-1] : 1
end

PowerShell

Scala

F#

C

C++

C++Builder

VC++

C#

Java

Objective-C

D

VB

VB.NET

Delphi

Ada

PL/SQL

T-SQL