PHP common functions, php_PHP tutorial-PHP Tutorial-php.cn

PHP common functions, php_PHP tutorial

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Release： 2016-07-12 09:05:22

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PHP common functions, php

1.PHP string

String declaration variable ='' or "" (usually single quotes are used because it is more convenient to write)

<span>$str</span> = 'Hello PHP'<span>;
</span><span>echo</span> <span>$str</span>;

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strpos calculates the position of the character in the string (starting from 0)

<span>$str</span> = 'Hello PHP'<span>;
</span><span>echo</span> <span>strpos</span>(<span>$str</span>,'o');  <span>//</span><span>计算字符在字符串中的位置</span>
<span>echo</span> '<br/>'<span>;
</span><span>echo</span> <span>strpos</span>(<span>$str</span>,'PH');

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substr intercepts string

<span>$str</span> = 'Hello PHP'<span>;
</span><span>//</span><span>截取字符串</span>
<span>$str1</span> = <span>substr</span>(<span>$str</span>,2,3); <span>//</span><span>从2位置开始截取，截取长度为3的字符串</span>
<span>echo</span> <span>$str1</span>;

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If the length parameter is not passed in, it will be intercepted from the specified position to the end of the string

str_split splits string fixed-length split (default length is 1)

<span>$str</span> = 'Hello PHP'<span>;
</span><span>//</span><span>分割字符串</span>
<span>$result</span> = <span>str_split</span>(<span>$str</span>);   <span>//</span><span>将结果保存到一个数组中</span>
<span>print_r</span>(<span>$result</span>);  <span>//</span><span>使用print_r输入一个数组</span>
<span>echo</span> '<br/>'<span>;
</span><span>$result1</span> = <span>str_split</span>(<span>$str</span>,2<span>);
</span><span>print_r</span>(<span>$result1</span>);

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explode (split character, string to be split) Split according to spaces

<span>$str</span> = 'Hello PHP Java C# C++'<span>;
</span><span>$result</span> = <span>explode</span>(' ',<span>$str</span><span>);
</span><span>print_r</span>(<span>$result</span>);

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Concatenation of strings

<span>$str</span> = 'Hello PHP Java C# C++'<span>;
</span><span>//</span><span>字符串的连接</span>
<span>$num</span> = 100<span>;
</span><span>$str1</span> = <span>$str</span>.'<br/>Objective-C '.<span>$num</span><span>;
</span><span>echo</span> <span>$str1</span><span>;
</span><span>echo</span> '<br/>'<span>;
</span><span>$str2</span> = "<span>$str</span><br/>Objective-C <span>$num</span>";    <span>//</span><span>另一中简便的写法</span>
<span>echo</span> <span>$str2</span>;

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2.PHP array

Array declaration PHP arrays are very dynamic and can store all types of data

<span>//</span><span>数组的声明方式</span>
<span>$arr</span> = <span>array</span><span>();
</span><span>$arr</span>[0] = 'Hello'<span>;
</span><span>$arr</span>[1] = 'World'<span>;
</span><span>$arr</span>[2] = 2<span>;
</span><span>$arr</span>[3] = 3.14<span>;
</span><span>print_r</span>(<span>$arr</span>);

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array_push()//Add an element
array_pop()//Delete the last element

<span>$arr</span> = <span>array</span><span>();
</span><span>for</span>(<span>$i</span>=0;<span>$i</span><100;<span>$i</span>++<span>){
    </span><span>array_push</span>(<span>$arr</span>,'Item'.<span>$i</span><span>);
}
</span><span>print_r</span>(<span>$arr</span>);

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Storing data through key-value pairs

<span>$arr</span> = <span>array</span><span>();
</span><span>$arr</span>['H'] = 'Hello'<span>;
</span><span>$arr</span>['W'] = 'World'<span>;
</span><span>print_r</span>(<span>$arr</span><span>);
</span><span>echo</span> '<br/>'<span>;
</span><span>echo</span> <span>$arr</span>['H'];

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Output: Array ( [H] => Hello [W] => World ) Hello

You can not only use a PHP array as an Array, but you can also use it as a Map
Array initialization

<span>$arr</span> = <span>array</span>('H'=>'Hello','W'=>'World');    <span>//</span><span>PHP数组初始化</span>
<span>print_r</span>(<span>$arr</span>);

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Array subscripts and key-value pairs can exist at the same time

<span>$arr</span> = <span>array</span>(0=>'Make',1=>'Tom','H'=>'Hello','W'=>'World'<span>);
</span><span>print_r</span>(<span>$arr</span><span>);
</span><span>echo</span> '<br/>'<span>;
</span><span>echo</span> <span>$arr</span>[0<span>];
</span><span>echo</span> '<br/>'<span>;
</span><span>echo</span> <span>$arr</span>['W'];

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Output: Array ( [0] => Make [1] => Tom [H] => Hello [W] => World ) Make World