PHP函式(副程式)

　　PHP函式可大略分為內建函式與自訂函式兩大類，其中內建函式種類繁多，無法一一介紹，在此僅提供與數學、網路、時間相關之內建函式。另外，有關檔案相關函式將在『PHP與檔案』中介紹。

內建函式

數學函式

絕對值函數：abs(數值)

程式	<? $x=-50; $a=abs($x); echo "\|".$x."\|=".$a; ?>	<? $x=-3.14; $a=abs($x); echo "\|".$x."\|=".$a; ?>	<? $x=1.23e-5; $a=abs($x); echo "\|".$x."\|=".$a; ?>
結果	\|-50\|=50	\|-3.14\|=3.14	\|1.23E-5\|=1.23E-5

角度與弧度互換、π：deg2rad(角度)；rad2deg(弧度)；pi()

	deg2rad(角度)	rad2deg(弧度)	π
程式	<? $deg=30; $rad=deg2rad($deg); echo $deg."°=".$rad."弧度"; ?>	<? $rad=1; $deg=rad2deg($rad); echo $rad."弧度=".$deg."°"; ?>	<? echo "π≒".pi(); ?>
結果	30°=0.5235987755983弧度	1弧度=57.295779513082°	π≒3.1415926535898

三角函數：sin()；cos()；tan()

程式	結果
<? $arg=30°; $rad=deg2rad($arg); echo "sin(".$arg.")=".sin($rad); echo "<br>cos(".$arg.")=".cos($rad); echo "<br>tan(".$arg.")=".tan($rad); ?>	sin(30°)=0.5 cos(30°)=0.86602540378444 tan(30°)=0.57735026918963

反三角函數：asin()；acos()；atan()

程式	<? $val=1; echo "sin<sup>-1</sup>(".$val.")=".asin($val)."弧度=".rad2deg(asin($val))."°"; echo "<br>cos<sup>-1</sup>(".$val.")=".acos($val)."弧度=".rad2deg(acos($val))."°"; echo "<br>tan<sup>-1</sup>(".$val.")=".atan($val)."弧度=".rad2deg(atan($val))."°"; ?>
結果	sin^-1(1)=1.5707963267949弧度=90° cos^-1(1)=0弧度=0° tan^-1(1)=0.78539816339745弧度=45°

乘冪(次方)：pow(底數,指數)

程式	<? echo pow(2,4); ?>	<? echo pow(2,0.5); ?>	<? echo pow(2,1/2); ?>	<? echo pow(2,-2); ?>
結果	16	1.4142135623731	1.4142135623731	0.25

常用對數：log10(正數)

程式	<? echo log10(2); ?>	<? echo log10(0); ?>	<? echo log10(-1); ?>
結果	0.30102999566398	-INF	NAN

四捨五入：round(數值,小數位數)

程式	<? echo round(pi(),3); ?>	<? echo round(pi(),0); ?>	<? echo round(pi(),-1); ?>
結果	3.142	3	0

小於或等於指定數的最大整數(高斯函數)：floor(數值)
大於或等於指定數的最小整數：ceil(數值)

程式	<? echo floor(3.14); ?>	<? echo floor(0); ?>	<? echo floor(-1.2); ?>
結果	3	0	-2

程式	<? echo ceil(3.14); ?>	<? echo ceil(0); ?>	<? echo ceil(-1.2); ?>
結果	4	0	-1

常用對數：sqrt(正數)

程式	<? echo sqrt(9); ?>	<? echo sqrt(2); ?>	<? echo sqrt(0); ?>	<? echo sqrt(-1); ?>
結果	3	1.4142135623731	0	NAN

常用對數：rand(最小數值,最大數值)

程式	<? echo rand(1,5); ?>	<? echo rand(-5,5); ?>	<? echo rand(1,1); ?>
結果	2	0	1

重整後數據會不一樣ㄛ！

網路資訊函式

遠端連線IP：$REMOTE_ADDR
遠端連線Host Name：$REMOTE_HOST

程式	<? echo $REMOTE_ADDR; ?>	<? echo $REMOTE_HOST; ?>
結果

本組函式建議配合『判斷變數是否已設定：isset()』使用

程式	<? if(isset($REMOTE_HOST)) echo $REMOTE_HOST; else echo $REMOTE_ADDR; ?>
結果

將IP轉換成HostName：gethostbyaddr(IP值)

程式	<? echo gethostbyaddr($REMOTE_ADDR); ?>
結果	Warning: gethostbyaddr(): Address is not a valid IPv4 or IPv6 address in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 427

發信函式：mail(收信位址,主旨,內容,表頭)

程式

<form method=post action=mailtest.php target=_blank>
您將發信給：rick@pc08.ccsh.tp.edu.tw<BR>
您的E-Mail：<input type=text name=from><BR>
信件主旨：<input type=test name=subject><BR>
信件內容：<textarea name=message rows=10 cols=30></textarea> <BR>
<input type=SUBMIT value=確定>
<input type=RESET value=清除>
</form>

mailtest.php
<?
$to="rick@pc08.ccsh.tp.edu.tw";
$m=mail($to,$subject,message,$from);
if($m) echo "信件已寄出";
else echo "信件寄出失敗"
?>

結果

時間函式

自GMT1970年1月1日0時0分0秒至現在的秒數：time()

程式	結果
<? echo time(); ?>	1726614293

依引數格式輸出日期與時間的值：date(引數格式)

引數格式	意義	程式	結果
a	顯示現在時間am或pm	<? echo date(a); ?>	Warning: Use of undefined constant a - assumed 'a' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 502 am
A	顯示現在時間AM或PM	<? echo date(A); ?>	Warning: Use of undefined constant A - assumed 'A' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 512 AM
y	以2位數字顯示西元年份	<? echo date(y); ?>	Warning: Use of undefined constant y - assumed 'y' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 522 24
Y	以4位數字顯示西元年份	<? echo date(Y); ?>	Warning: Use of undefined constant Y - assumed 'Y' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 532 2024
m	以2位數字顯示月份	<? echo date(m); ?>	Warning: Use of undefined constant m - assumed 'm' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 542 09
n	顯示月份	<? echo date(n); ?>	Warning: Use of undefined constant n - assumed 'n' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 552 9
F	以英文字顯示月份	<? echo date(F); ?>	Warning: Use of undefined constant F - assumed 'F' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 562 September
M	以3位英文字顯示月份	<? echo date(M); ?>	Warning: Use of undefined constant M - assumed 'M' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 572 Sep
j	顯示日期	<? echo date(j); ?>	Warning: Use of undefined constant j - assumed 'j' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 582 18
d	以2位數字顯示日期	<? echo date(d); ?>	Warning: Use of undefined constant d - assumed 'd' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 592 18
w	以數字顯示星期幾 (0--星期日‧‧‧6--星期六)	<? echo date(w); ?>	Warning: Use of undefined constant w - assumed 'w' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 603 3
l	以英文字顯示星期	<? echo date(l); ?>	Warning: Use of undefined constant l - assumed 'l' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 613 Wednesday
D	以3位英文字顯示星期	<? echo date(D); ?>	Warning: Use of undefined constant D - assumed 'D' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 623 Wed
h	以2位數字顯示12小時制的時	<? echo date(h); ?>	Warning: Use of undefined constant h - assumed 'h' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 633 07
g	顯示12小時制的時	<? echo date(g); ?>	Warning: Use of undefined constant g - assumed 'g' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 643 7
H	以2位數字顯示24小時制的時	<? echo date(H); ?>	Warning: Use of undefined constant H - assumed 'H' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 653 07
G	顯示24小時制的時	<? echo date(G); ?>	Warning: Use of undefined constant G - assumed 'G' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 663 7
i	以2位數字顯示分	<? echo date(i); ?>	Warning: Use of undefined constant i - assumed 'i' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 673 04
s	顯示秒數	<? echo date(s); ?>	Warning: Use of undefined constant s - assumed 's' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 683 53
L	顯示該年是否為閏年 (1--閏年；0--平年)	<? echo date(L); ?>	Warning: Use of undefined constant L - assumed 'L' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 694 1
t	顯示該月份有幾天	<? echo date(t); ?>	Warning: Use of undefined constant t - assumed 't' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 704 30
U	自GMT1970年1月1日0時0分0秒至現在的秒數(同time()函式)	<? echo date(U); ?>	Warning: Use of undefined constant U - assumed 'U' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 715 1726614293
z	顯示一年的第幾天	<? echo date(z); ?>	Warning: Use of undefined constant z - assumed 'z' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 725 261

取得距GMT1970年1月1日0時0分0秒的秒數之日期與時間陣列：getdate(秒數)
其陣列索引如下

陣列索引	意義	程式	結果
year	以4位數字顯示西元年份	<? $d=getdate(); echo $d[year]; ?>	Warning: Use of undefined constant year - assumed 'year' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 747 2024
mon	以2位數字顯示月份	<? $d=getdate(); echo $d[mon]; ?>	Warning: Use of undefined constant mon - assumed 'mon' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 759 9
month	以英文字顯示月份	<? $d=getdate(); echo $d[month]; ?>	Warning: Use of undefined constant month - assumed 'month' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 771 September
mday	以數字顯示日	<? $d=getdate(); echo $d[mday]; ?>	Warning: Use of undefined constant mday - assumed 'mday' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 783 18
wday	以數字顯示星期	<? $d=getdate(); echo $d[wday]; ?>	Warning: Use of undefined constant wday - assumed 'wday' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 795 3
weekday	以英文字顯示星期	<? $d=getdate(); echo $d[weekday]; ?>	Warning: Use of undefined constant weekday - assumed 'weekday' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 807 Wednesday
hours	以數字顯示時	<? $d=getdate(); echo $d[hours]; ?>	Warning: Use of undefined constant hours - assumed 'hours' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 819 7
minutes	以數字顯示分	<? $d=getdate(); echo $d[minuts]; ?>	Warning: Use of undefined constant minutes - assumed 'minutes' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 831 4
seconds	以數字顯示秒	<? $d=getdate(); echo $d[seconds]; ?>	Warning: Use of undefined constant seconds - assumed 'seconds' (this will throw an Error in a future version of PHP) in /volume1/homes/rick/www/homepage/phpfunction.php3 on line 843 53

檢驗日期是否正確：checkdate(數字月份,數字日期,數字年份)

程式

結果

<form method=post action=checkdate.php3 target=_blank>
請輸入日期：<BR>西元
<input type=text size=4 name=year>年
<input type=text size=2 name=month>月
<input type=text size=2 name=day>日<BR>
<input type=SUBMIT value=確定>
<input type=RESET value=清除>
</form>

checkdate.php3
<?
if(checkdate($month,$day,$year))
{
    echo "您輸入的日期為：";
    echo "西元".$year."年".$month."月".$day."日";
}
else
{
    echo "你唬我ㄚ！哪有";
    echo "西元".$year."年".$month."月".$day."日　這一天";
}
?>

自訂函式

function 函式名稱(傳入值1,傳入值2,‧‧‧,傳入值n)
{
global $全域變數名稱;
‧‧‧程式‧‧‧
return $傳回值;
}

根據呼叫方式分下列情況討論

自身呼叫

程式	結果
<? //副程式 function permutation($n,$m) { $per=1; for($i=$n;$i>($n-$m);$i--) { $per=$per*$i; } return $per; } //主程式 $p1=permutation(3,1); $p2=permutation(3,2); $p3=permutation(3,3); echo "P<sub>1</sub><sup>3</sup>=".$p1; echo "<BR>P<sub>2</sub><sup>3</sup>=".$p2; echo "<BR>P<sub>3</sub><sup>3</sup>=".$p3; ?>	P₁³=3 P₂³=6 P₃³=6

呼叫其他檔案副程式：inclode("檔案名稱")

程式

結果

//主程式
<?
include ( "combination.php3");
$c1=combination(3,1);
$c2=combination(3,2);
$c3=combination(3,3);
echo "C<sub>1</sub><sup>3</sup>=".$c1;
echo "<BR>C<sub>2</sub><sup>3</sup>=".$c2;
echo "<BR>C<sub>3</sub><sup>3</sup>=".$c3;
?>

//副程式combination.php3
<?
function combination($n,$m)
{
$com=1;
$q=1;
for($i=$n;$i>($n-$m);$i--)
{
$com=$com*$i;
$q=$q*($n-$i+1);
}
$com=$com/$q;
return $com;
}
?>

C₁³=3
C₂³=3
C₃³=1

By Rick 2003

程式	<? $x=-50; $a=abs($x); echo "\|".$x."\|=".$a; ?>	<? $x=-3.14; $a=abs($x); echo "\|".$x."\|=".$a; ?>	<? $x=1.23e-5; $a=abs($x); echo "\|".$x."\|=".$a; ?>
結果	\|-50\|=50	\|-3.14\|=3.14	\|1.23E-5\|=1.23E-5