Summary of types of PHP printing functions_PHP tutorial-PHP Tutorial-php.cn

Summary of types of PHP printing functions_PHP tutorial

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Release： 2016-07-15 13:30:41

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In PHP printing function 1 echo()

can output multiple strings at the same time and can have multiple parameters. , parentheses are not required, and there is no return value.

PHP printing function 2 print()

can only output one string and one parameter at the same time, requires parentheses, and has a return value. When its execution fails, it returns flase. The usage of print is very similar to that of C language, so % in the output content will be specially interpreted.

PHP printing function 3 die();

has two functions: first output the content, and then exit the program . (Commonly used in linked servers and databases)

mysql_connect("locahost","root","root") or die("Linked server failed!");

PHP printing function 4 printf();

printf("Parameter 1", Parameter 2): Parameter 1 = output format; Parameter 2 = output variable. ($s: according to string; $d: according to integer; $b: according to binary; $x: according to hexadecimal; $o: according to octal; $f: according to floating point)

<ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span> ?php  </span></span></li><li><span>$</span><span class="attribute">num</span><span>=</span><span class="attribute-value">100</span><span>.001;  </span></li><li class="alt"><span>printf("%d",$num); //100  </span></li><li><span>printf("%s",$num); //100.001  </span></li><li class="alt"><span>printf("%s---%d---%b---%x---%o---%f",$num,$num,$num,$num,$num,$num)  </span></li><li><span>//100.001---100---1100100---64---144---1001.00100  </span></li><li class="alt"><span>printf("%.2f",$num); //100.00 (小数点保留2位)  </span></li><li><span>printf("%.1f",$num); //100.0 (小数点保留1位)  </span></li><li class="alt"><span>printf("%`#10s",$num); //###100.001  </span></li><li><span>printf("%`@10s",$num); //@@@100.001  </span></li><li class="alt"><span>printf("%`_10s",$num); //___100.001  </span></li><li><span>printf("%`#-10s",$num); //100.001###  </span></li><li class="alt"><span>printf("%`@-10s",$num); //100.001@@@  </span></li><li><span>printf("%`_-10s",$num); //100.001___  </span></li><li class="alt"><span>printf("%`#20s",$num); //#############100.001  </span></li><li><span class="tag">?></span><span> </span></span></li></ol>

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PHP printing function 5 sprintf();

This cannot be output directly, assign it to a first variable, and then output the variable.

<ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span> ?php  </span></span></li><li><span>$</span><span class="attribute">num</span><span>=</span><span class="attribute-value">100</span><span>.001;  </span></li><li class="alt"><span>$</span><span class="attribute">a</span><span>=</span><span class="attribute-value">sprintf</span><span>("%d",$num);  </span></li><li><span>echo $a; //100  </span></li><li class="alt"><span class="tag">?></span><span> </span></span></li></ol>

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PHP printing function 6 print_r();

Function: only For output array.

PHP printing function 7 var_dump();

Function: Output the content, type or string content, type, length of the variable. Often used for debugging.

<ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span> ?php  </span></span></li><li><span>$</span><span class="attribute">a</span><span>=</span><span class="attribute-value">100</span><span>;  </span></li><li class="alt"><span>var_dump($a); //int(3) 100  </span></li><li><span class="tag">?></span><span> </span></span></li></ol>

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