PHP 关于字符串操作的练习

题目太长不易截图，代码复制粘贴即可懂

• 练习一

<?php
$name = "stefen";
$call = "10795856";
$motto = "If you shed tears when you miss the sun,then you would miss the stars";
$value =  $name.$call.$motto;
echo strlen($value);

• 练习二

<?php
//$str = 'hello';
//$str = $str . '中文';
//echo $str;
//
//
////单引号双引号不同之处
//$num = 100;
//echo 'num' . $num . '<br/>';
//echo 'num=$num <br/>';
//echo "num=$num <br/>";
//system("dir");

//第一题 4. 定义一个数组, 并使用{1,2,3,4,5,6,7,8,9}来初始化. 然后输出数组的内容*/
$arr = array(1,2,3,4,5,6,7,8,9);
print_r($arr);
echo "<br/>";

//第二题 /* 5. 定义一个数组, 并使用{"小明",18,1.8,"男"}来初始化. 然后输出数组的内容*/
$arr1 = array('小明','18','1.8','男');
print_r($arr1);
echo "<br/>";
//第三题   /* 6. 使用数组保存以下内容: 姓名=小明 , 年龄=18, 身高=1.8, 性别='男', 并输出数组的内容*/
$arr2 = array('姓名' =>'小明','年龄'=>'18','身高'=>'1.8','性别'=>'男');
echo $arr2[姓名];
echo $arr2[年龄];
echo $arr2[身高];
echo $arr2[性别];
//print_r($arr2,true);
echo "<br/>";
//第7题  7. 使用循环遍历上题数组中的内容
foreach ($arr2 as $key => $value){
    echo "key=$key value=$value<br/>
";
}
echo "<br/>";

//第8题8. 将以下内容保存到二维数组中.
// *   - 水果
// *      - 苹果
// *      - 雪梨
// *      - 香蕉
// *   - 盖饭
// *      - 青椒肉丝盖饭
// *      - 胡萝卜肉丝盖饭
// *      - 西红柿鸡蛋盖饭
$arr3 = [
            '水果' => ['苹果','雪梨','香蕉'],
            '盖饭' => ['青椒肉丝盖饭','胡萝卜肉丝盖饭','西红柿鸡蛋盖饭']
        ];
print_r($arr3);
echo "<br/>";
//第九题  将上一题的内容输出到网页 , 并且输出为html的列表标签*/
foreach ($arr3 as $title => $item){
        echo "<ul style='background:azure; display:block;200px;'><h4>$title</h4>
";
        foreach ($item as $value){
            echo "	<li>$value</li>
";
        }
        echo "</ul>
";
}

//i++：是先赋值，再加一，举个例子来看下
//++i: 先加1在赋值

• 练习三

<?php
$a = "i want to fly,Fly in the sky,fly to the Higher!";
echo strtoupper($a);//全部转换为大写
echo "<br/>";
echo strtolower($a);//全部转换为小写
echo "<br/>";
echo lcfirst($a);//句首字母转换为大写
echo "<br/>";
echo ucwords($a);//每个单词首字母转换为大写
echo "<br/>";

• 练习四

<?php
$name = "stefen";
$call = "10795856";
$motto = "If you shed tears when you miss the sun,then you would miss the stars";
$value =  $name.$call.$motto;
echo strlen($value);

• 练习五

<?php
//$phone = "17943596998137738847091593794520818397664593";
//strrchr()
$string = "I LOVE YOU,MY COUNTRY";
echo substr($string,2,5);
echo "<br/>";
echo substr($string,11,2);
echo "<br/>";
echo substr($string,14);

• 练习六

<?php
$demo = "Demon is an English teacher.17847564092";
echo $demo;
echo "<br/>";
echo "删掉前的长度是：";echo strlen($demo);
echo "<br/>";
$value = preg_replace('/[17847564092]+/i',"",$demo);
echo $value;
echo "<br/>";
echo "删掉后的长度是：";echo strlen($value);

• 练习七

<?php
$string = "FunCTION_deFINe_TYpe";
$a = strtolower($string);   //先全部转换成小写strtolower
$b = str_replace("_"," ",$a);//将_转换成空格str_replace
$c = ucwords($b);//再将每个首字母转换成大写ucwords
$d = str_replace(" ","_",$c);//将空格转换成_  str_replace
echo $d;

• 练习八

<?php
$phone = "17943596998137738847091593794520818397664593";
$a = strrpos($phone,'9');
echo "数字9最后一次出现的位置是：";echo $a;