Loops

While 语句

while denotes a loop that iterates as long as its given condition evaluates as true:

let counter = 5;
while counter {
    let counter -= 1;
}

Loop 语句

除了 while, loop 还可用于创建无限循环:

let n = 40;
loop {
    let n -= 2;
    if n % 5 == 0 { break; }
    echo x, "\n";
}

For 语句

for 是一种控制结构, 允许遍历数组或字符串:

for item in ["a", "b", "c", "d"] {
    echo item, "\n";
}

可以通过为键和值提供变量来获取哈希中的键：

let items = ["a": 1, "b": 2, "c": 3, "d": 4];

for key, value in items {
    echo key, " ", value, "\n";
}

还可以指示` for </ 0>循环以相反的顺序遍历数组或字符串：</p>

let items = [1, 2, 3, 4, 5];
for value in reverse items {    echo value, "\n";}`</pre> 
` for </ 0>循环可用于遍历字符串变量：</p>
string language = "zephir"; char ch;
for ch in language {    echo "[", ch ,"]";}`</pre> 
按相反顺序：
string language = &#34;zephir&#34;; char ch;

for ch in reverse language {
    echo &#34;[&#34;, ch ,&#34;]&#34;;
}

遍历一系列整数值 可以写成如下：
for i in range(1, 10) {
    echo i, &#34;\n&#34;;
}

要避免对未使用的变量发出警告，可以在for语句中使用匿名变量，方法是使用占位符` _ </ 0>替换变量名称：</p>
使用键, 但忽略该值

for key, _ in data {    echo key, "\n";}`</pre> 

Break 语句break 结束当前 while、for 或 loop 语句的执行:
for item in [&#34;a&#34;, &#34;b&#34;, &#34;c&#34;, &#34;d&#34;] {
    if item == &#34;c&#34; {
        break; // exit the for
    }
    echo item, &#34;\n&#34;;
}


Continue 语句在循环结构中使用 continue 跳过当前循环迭代的其余部分, 并在条件计算时继续执行, 然后在下一次迭代的开始时继续执行。
let a = 5;
while a &gt; 0 {
    let a--;
    if a == 3 {
        continue;
    }
    echo a, &#34;\n&#34;;
}