09. februar 2003 - 13:15Der er
41 kommentarer og 1 løsning
Tjekke indholdet af form?
Jeg har lavet en form, hvor der skal indtastes nogle tal, som så skal beregnes på næste side. Hvis indholdet af felterne er bogstaver, skal den selvfølgelig komme med fejl. Hvordan tjekker jeg om indholdet er tal?
--- snip --- What is the difference between echo and print? Which is faster, echo or print? Jun 8th, 1999 09:00
Nathan Wallace Rasmus Lerdorf There is a difference between the two, but speed-wise it should be irrelevant which one you use. print() behaves like a function in that you can do:
$ret = print "Hello World";
And $ret will be 1
That means that print can be used as part of a more complex expression where echo cannot. print is also part of the precedence table which it needs to be if it is to be used within a complex expression. It is just about at the bottom of the precendence list though. Only "," AND, OR and XOR are lower.
echo is marginally faster since it doesn't set a return value if you really want to get down to the nitty gritty.
If the grammar is:
echo expression [, expression[, expression] ... ]
Then
echo ( expression, expression )
is not valid. ( expression ) reduces to just an expression so this would be valid:
echo ("howdy"),("partner");
but you would simply write this as:
echo "howdy","partner";
if you wanted to use two expression. Putting the brackets in there serves no purpose since there is no operator precendence issue with a single expression like that. --- / snip ---
PS, den snip jeg har fundet kommer faktisk samme sted fra som det det andet spm. link til... nok fordi linket står i manualen...
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