T Hc PHP
By traibingo 1 | P a g e

1. Hằng và biến
Nn ng hc l vi hn. OK, No Star
where
- Gic, mt hng s nh m duy nha hng
s, trong Tin hng s nh m duy nht tro 
 s d a hng s 
-  i vi bin. Mt bin trong lc s d  m 
n. S i ta gng s (gi  trong
   ca bin s 


 tu kin d  linh bt k t u $
 c a bi:
nh mt bi
nh mt bi

Bn cn bit rt chu ch bao g s, ch u
g bin ch  ng
hm c
bin bu b s (0.. 9)

 a du $  n PHP t ng kh
 ci vi kiu d lin) hoi vi kiu d liu s. Bn
s c biu d li

  n, bn s d
 cn;


3.Định nghĩa hằng

c s d to mt hng s:

n ca hng");
:
ng COMPANY v 
ng diem_so v i );

Sau khi mt hng s c t s dng  c



4. Một số hằng xây dựng sẵn (built in constant)

a mt s hng sc dng sn vi
T Hc PHP
By traibingo 3 | P a g e

ch c mng)

Hng s PHP_VERSION ch n ca b n ti.
Hng PHP_OS ch nh h y.

)

_FILE_and_LINE_ tr v n
th

p mt s  

mt chui:

N c n $str, bin $str s t i
s 
$x=4+$str;//$x =756304

 ca bii

ec

Chuyn kiu chui phc sau:
- Ch nhng chui b  s. Nu chui bu bng m s hp l,
chu  cng h tr v 0. VD: chui
"35 tui" s i "tui 35" s ch  0.

- Mt chui s ch  kiu double n kic
 bao g chui. Chui "3.4", "-4.2" s  th-
4.2. Nu m  kiu s th ca chu
t s i "3.4 dollar" s  

Trong vic cng vi chui chuyn kiu, PHP s thc hin "la kiu" gia 2 kiu s. Nu bn thc
hin m hc gia kiu th s  thc

t s 
 thc
u s thc , = 2.0
$d = $c+"6th" //u s thc = 8.0

Ép kiểu dữ liệu


u thc
 t s  7

- c s d nh xem bit mt  
u bi v true. Trong trung hc l v 
tr false;
- c s d hu b bin $ten_bien, gi nh b chim
dng ca bi
Ctip