# puts 10
# puts -8
# puts 2.5
# puts 1_000_000
# e を使った表現
puts 1.2e3 # 1.2かける10の3乗
puts 1.2e-3 # 1.2かける10の-3乗
月: 2024年2月
ruby 数値
puts 10
puts -8
puts 2.5
puts 1_000_000
ruby puts
puts 10;
Javascript スプレッド構文
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
// let num = 10;
// const numBackup = num;
// num = 99;
// console.log(num);
// console.log(numBackup);
const nums = [10, 20, 30];
const numBackup = [...nums];
nums[0] = 99;
console.log(nums);
console.log(numBackup);
}
Javascript 値のバックアップ
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
// let num = 10;
// const numBackup = num;
// num = 99;
// console.log(num);
// console.log(numBackup);
const nums = [10, 20, 30];
const numBackup = nums;
nums[0] = 99;
console.log(nums);
console.log(numBackup);
}
Javascript オブジェクト
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
const moreScores = {
shiro: 77,
goro: 88,
};
const scores = {
taro: 80,
jiro: 70,
saburo: 90,
...moreScores,
};
// const {taro, jiro, saburo} = scores;
const {taro, ...others} = scores;
console.log(taro);
// console.log(jiro);
// console.log(saburo);
console.log(others);
}
Javascript スプレッド構文
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
const moreScores = [77, 88];
const scores = [70,90,80,85, ...oreScores];
const [first, ...others] = scores;
console.log(first);
console.log(others);
}
Javascript レスト構文
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
const scores = [70,90,80,85];
const [first, ...others] = scores;
console.log(first);
console.log(others);
}
Javasript 分割代入
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
let start = 'Tokyo';
let goal = 'Osaka';
//start = goal;
//goal = start;
//let temp = "";
//temp = start;
//start = goal;
//goal = temp;
[goal, start] = [start, goal]
console.log(start);
console.log(goal);
}
Javascript 分割代入
index.html
<!DOCTYPE html>
<html lang="ja">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>My JavaScript</title>
</head>
<body>
<script src="main.js"></script>
</body>
</html>
main.js
'use strict';
{
const scores = [70, 90, 80, 85];
// const first = scores[0];
// const second = scores[1];
// const third = scores[2];
// const fourth = scores[3];
const [first, second, third, fourth] = scores;
console.log(first);
console.log(second);
console.log(third);
console.log(fourth);
}