PHP3 Chinese Document (cont. 5)

Chinese arithmetic operator





These jobs are similar to those taught in basic schools.





　





Table 7-1. Arithmetic Operators (table 7-1 arithmetic operator)





Example Name result


$a + $b addition Sum of $a and $b.? /FONT>


$a-$b subtraction remainder of $b subtracted from $a.? /FONT>


$a * $b multiplication Product of $a and $b.? /FONT>


$a/$b division dividend of $a and $b.? /FONT>


$a% $b modulus remainder of $a divided by $b.





　





where the division operator "/" returns an integer value (the result of integer division) if two operands are integers (or strings that are converted to integers). If any of the operands are floating-point numbers, floating-point operations are performed.





string operator





This place has only one real string operator: concatenate symbol ".".





　





$a = "Hello"; $b = $a. " World! ";





//Now $b = "Hello world!"





Assignment operator





the basic assignment operator is "=". You tend to think that it means "equals". Don't think like that, it really means that the left-hand operand gets the value of the right expression.





　





the meaning of an assignment expression is the assignment of a value. In other words, the value of "$a = 3" is 3. This allows you to do things like this:





　





$a = ($b = 4) + 5;





//$a is equal to 9 now, and $b has been set to 4.





　





as a supplement to the assignment operator, there is also a combination operator for binary numbers and word Fu, which allows you to use the value of an assignment expression on the assignment. For example:





　





$a = 3;





$a + 5; Sets $a to 8, as if we had said: $a = $a + 5;





$b = "Hello";





$b. = "there!"; Sets $b to "Hello there!" and just like $b = $b. "There!";





bit operator




The
bit operator allows you to fine manipulate each bit of data.





　





Table 7-2. Bitwise Operators (table 7-2-bit operator)





Example Name result


$a & $b and Bits are set in both $a and $b are set.? /FONT>


$a | $b or Bits that are set in either $a or $b are set.? /FONT>


~ $a?/font> not Bits so are set in $a are not set, and vice versa.





logical operator





Table 7-3. Logical Operators (table 7-3 logical operators)





　





Example Name result?/font>


$a and $b and true of both $a and $b are true.? /FONT>


$a or $b or?/font> true if either $a or $b is true.? /FONT>


$a xor $b or?/font> true if either $a Or $b is True, but not both.? /FONT>


! $a not?/font> True if $a is not True.? /FONT>


$a && $b and?/font> true of both $a and $b are true.? /FONT>


$a | | $b or?/font> True if either $a Or $b is True.





comparison operator




The
comparison operator, as its name shows, allows you to compare two values.





　





Table 7-4. Comparson Operators (table 7-4 comparison operator)





Example Name result?/font>


$a = = $b equal?/font> True If $a is Equal to $b.? /FONT>


$a!= $b not equal True if $a was not equal to $b. /FONT>


$a < $b less than?/font> True If $a is strictly less than $b.? /FONT>


$a > $b Greater than?/font> True If $a is strictly Greater than $b.? /FONT>


$a <= $b less than or equal to?/font> True if $a is less than or equal to $b. /FONT>


$a >= $b Greater than or equal to?/font> True if $a is Greater than or equal to $b.