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Programming-Idioms

# 223 for else loop
Loop through list items checking a condition. Do something else if no matches are found.

A typical use case is looping through a series of containers looking for one that matches a condition. If found, an item is inserted; otherwise, a new container is created.

These are mostly used as an inner nested loop, and in a location where refactoring inner logic into a separate function reduces clarity.
New implementation

Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating material.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations 
(def my-col [2 4 6 8 5])

(if (seq (filter odd? my-col))
  "contains odds"
  "no odds found")

(if (some #{5} my-col)
  "contains element"
  "doesn't contain element")
#include <list>
bool found = false;
for (const auto item : items) {
  if (item == "baz") {
    baz();
    found = true;
    break;
  }
}
if (!found) {
  DoSomethingElse();
}
#include <algorithm>
if (std::any_of(items.begin(), items.end(), condition))
    baz();
else
    DoSomethingElse();
using System.Linq;
if (!items.Any(i => MatchesCondition(i)))
{
	DoSomethingElse();
}
print(items.any((element) => element == "baz")
    ? "found it"
    : "did not find it");
  found = .false.
  do i=1,size(items)
    if (items(i) == "asdf") then
      found = .true.
      exit
    end if
  end do
  if (.not. found) call do_something

items := []string{"foo", "bar", "baz", "qux"}

for _, item := range items {
    if item == "baz" {
        fmt.Println("found it")
        goto forelse
    }
}
{
    fmt.Println("never found it")
}
forelse:
println(items.any { it == "baz" } ? 'found' : 'not found')

const found = items.some(condition);

if (!found) doSomethingElse();
Predicate<Item> condition;
items.stream()
	.filter(condition)
	.findFirst()
	.ifPresentOrElse(
		item -> doSomething(i),
		() -> doSomethingElse());
boolean b = false;
for (int i = 0; i<items.length; i++) {
	if (items[i] == something) {
		doSomething();
		b = true;
	}
}
if (!b)
	doSomethingElse();
items.find { it == "baz" }
  ?.let { println("found it") }
  ?: println("never found it")
if(items.any { it == "baz" })
  println("found it")
else 
  println("never found it")
(loop for item in items
      when (check-match item) return (do-something item)
      finally (return (do-something-else))
local function list_cond(t,cond)
 for _,v in ipairs(t) do
  if cond(v)==true then return true end
 end
 return false
end
if list_cond(items,function(x) return x==0 end) then
 print("did find 0")
else
 print("didn't find 0")
end
function search(array $haystack, string $needle, callable $doSuccess, callable $doFail)
{
    foreach ($haystack as $item) {
        if ($item === $needle) {
            $doSuccess();
            return;
        }
    }
    $doFail();
}

$items = ["foo", "bar", "baz", "qux"];
search(
    $items,
    "baz",
    static function () {
        echo "found it";
    },
    static function () {
        echo "not found";
    }
);
Found := False;
for Item in Items do
begin
  if Item.MatchesCondition then
  begin
    Found := True;
    Break;
  end;
end;
if not Found then 
  DoSomethingElse;
my $found_match = 0;
foreach my $item (@items) {
    if ($item eq 4) {
        print "Found $item\n";
        $found_match = 1;
        last;
    }
}
if (!$found_match) {
    print "Didn't find what I was looking for\n";
}
for item in items:
    if item == 'baz':
        print('found it')
        break
else:
    print('never found it')
items = ['foo', 'bar', 'baz', 'qux']
puts items.any?("baz") ? "found it" : "never found it"
items
    .iter()
    .find(|&&item| item == "rockstar programmer")
    .or_else(|| {
        println!("NotFound");
        Some(&"rockstar programmer")
    });
if 'search: loop {
    for i in items {
        if i == &"qux" {
            println!("found it");
            break 'search false;
        }
    }
    break 'search true
} {
    println!("not found!");
}
'label: {
	for &item in items {
		if item == "baz" {
			println!("found");
			break 'label;
		}
	}
	println!("not found");
}
let mut found = false;
for item in items {
    if item == &"baz" {
        println!("found it");
        found = true;
        break;
    }
}
if !found {
    println!("never found it");
}
if let None = items.iter().find(|&&item| item == "rockstar programmer") {
        println!("NotFound");
    };

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