Mobile app interface programming technology - learn to implement PHP strings

• Single quotes, double quotes

In PHP, the definition of a string can use English single quotes ' ' or English double quotes " ". However, PHP allows us to include string variables directly within double-quoted strings. The content in single quote strings is always considered to be ordinary characters.

<code><span>$str</span>=<span>'hello'</span>;
<span>echo</span><span>"str is <span>$str</span>"</span>; //运行结果: str is hello
<span>echo</span><span>'str is $str'</span>; //运行结果: str is <span>$str</span></code>

• Concatenation of strings

Use English dots in PHP to connect two strings.

<code><span><span><?php</span><span>$i</span>=<span>'I'</span>;
<span>$love</span>=<span>' Love'</span>;
<span>$you</span>=<span>' You'</span>;
<span>//连接一下三个字符串</span><span>echo</span><span>$i</span>.<span>$love</span>.<span>$you</span>;
<span>?></span></span></code>

• Remove spaces from the beginning and end of a string

  There are three functions in PHP that can remove spaces from a string
  trim removes spaces from both ends of a string.
  rtrim is to remove the spaces on the right side of a string, where r is the abbreviation of right.
  ltrim removes spaces from the left of a string, where l is the abbreviation of left.

<code><span><span><span><?php</span><span>//</span><span>$str</span>=<span>"      空格要去掉      "</span>;

<span>echo</span><span>"jar"</span>.trim(<span>$str</span>).<span>"len"</span>.<span>"<br>"</span>;

<span>echo</span><span>"jar"</span>.ltrim(<span>$str</span>).<span>"len"</span>.<span>"<br>"</span>;

<span>echo</span><span>"jar"</span>.rtrim(<span>$str</span>).<span>"len"</span>.<span>"<br>"</span>;

<span>?></span></span></span></code>

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