Detecting negative numbers

Question

I was wondering if there is any way to detect if a number is negative in PHP   I have the following code    profitloss    result- gt date sold price -  result- gt date bought price    I need to find out if  profitloss is negative and if it is  I need to echo out that it is

User · Answer

You could check if  profitloss  lt  0  if   profitloss  lt  0       echo  Less than 0 n   endif

User · Answer

You could use a ternary operator like this one  to make it a one liner   echo   profitloss  lt  0     false     true

User · Answer

Don t get me wrong  but you can do this way     function nagitive check  value   if  isset  value        if  substr strval  value   0  1      -        return  It is negative lt br gt      else       return  It is not negative  lt br gt                Output   echo nagitive check -100       It is negative echo nagitive check 200       It is not negative  echo nagitive check 200-300       It is negative echo nagitive check 200-300 1000       It is not negative

User · Answer

if x  lt  0  if abs x     x  if substr strval x   0  1      -

User · Answer

Just multiply the number by -1 and check if the result is positive

User · Answer

if   profitloss  lt  0       echo  The profitloss is negative       Edit  I feel like this was too simple an answer for the rep so here s something that you may also find helpful   In PHP we can find the absolute value of an integer by using the abs   function  For example if I were trying to work out the difference between two figures I could do this    turnover   10000   overheads   12500    difference   abs  turnover- overheads    echo  The Difference is    difference    This would produce The Difference is 2500

User · Answer

if    profitloss  lt  0        echo  negative

User · Answer

I believe this is what you were looking for   class Expression       protected  expression      protected  result       public function   construct  expression             this- gt expression    expression             public function evaluate              this- gt result   eval  return    this- gt expression               return  this             public function getResult             return  this- gt result           class NegativeFinder       protected  expressionObj       public function   construct Expression  expressionObj             this- gt expressionObj    expressionObj             public function isItNegative              result    this- gt expressionObj- gt evaluate  - gt getResult             if  this- gt hasMinusSign  result                 return true            else               return false                       protected function hasMinusSign  value            return  substr strval  value   0  1      -              Usage    soldPrice   1   boughtPrice   2   negativeFinderObj   new NegativeFinder new Expression   soldPrice -  boughtPrice      echo   negativeFinderObj- gt isItNegative       It is negative      It is not negative        Do however note that eval is a dangerous function  therefore use it only if you really  really need to find out if a number is negative    -

User · Answer

I assume that the main idea is to find if number is negative and display it in correct format   For those who use PHP5 3 might be interested in using Number Formatter Class - http   php net manual en class numberformatter php  This function  as well as range of other useful things  can format your number    profitLoss   25000 - 55000    a  new  NumberFormatter  en-UK    NumberFormatter  CURRENCY     a- gt formatCurrency  profitLoss   EUR       would display     30 000 00    Here also a reference to why brackets are used for negative numbers  http   www open edu openlearn money-management introduction-bookkeeping-and-accounting content-section-1 7

User · Answer

Can be easily achieved with a ternary operator   is negative    profitloss  lt  0   true   false

[php] Detecting negative numbers

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