I am trying to use a text variable value in an if condition parathesis.
Using PHP
<?php
$a = 1;
$b = 2;
$condition = '$a < $b';
if($condition)
{ echo "Condition is TRUE"; } else
{ echo "Condition is FALSE"; }
?>
Expected Answer:
Condition is TRUE
Related
I am trying to reduce/simplify the following code as it looks to have repeated elements:
<?php
if ($condition == true) {
if ($a > $b*0.5) {
echo "successful";
}
else {
echo "missed";
}
}
else {
if ($a > $b) {
echo "successful";
}
else {
echo "missed";
}
}
I don't want to use functions because if I did, I would have to define all the database things again.
<?php
if ( (condition1 && ($a > $b*0.5)) || (!condition1 && ($a > $b)) ) {
echo "successful";
else {
echo "missed";
}
?>
Your Code is missed Two (Semicoloumns)}.
Try By this
<?php
$a == 2;
$b == 4;
if ($a == 2 && $a > $b*0.5) {
echo "Suuccess";
}elseif($a != 2 && $a > $b){
echo "Suuccess";
}else{
echo "Fails";
}
In order to simplify your conditions, if the output is boolean (so only two outcomes possible) you could go with either one as default and only change it to the other depending on your decisions.
<?php
$outcome = false;
if($condition1 && ($a > ($b * 0.5))) {
$outcome = true;
}
else if($a > $b) {
$outcome = true;
}
if($outcome) {
echo "succesful";
}
else {
echo "missed";
}
This also combines the technique proposed by Sofyan Thayf to use boolean operators to merge conditions.
Another approach is to put the condition into a function and return early if succesful and have a missed fallthrough like
<?php
function decide($a, $b, $condition1) {
if($condition1 && ($a > ($b * 0.5)))
return true;
if($a > $b)
return true;
return false;
}
if(decide($a, $b, $condition1)) {
echo "succesful";
}
else {
echo "missed";
}
Both approaches enable you to extract the "same code" (being the echo) and IMHO add to readability and extensibility.
<?php
$factor = $condition ? 0.5 : 1;
if ($a > $b * $factor) {
echo "Hit";
}
else {
echo "Miss";
}
Could be further reduced using two ternary operators:
echo $a > $b * ($condition ? 0.5 : 1)
? 'Hit'
: 'Miss';
Ternary operators are useful shorthand for if/else conditionals.
I want to check different conditions into if statement based on different scenario (Will get the $status value as 'Y' or 'N'). Please check the code below and let me know the issue here.
$fstrto = "10";
$cstrto = "7";
if($status == 'N')
{
$cond = "$fstrto <= $cstrto";
}
else
{
$cond = "$fstrto >= $cstrto";
}
if($cond)
{
echo "Success";
}
This code is not working as it takes the "$fstrto <= $cstrto" as variable.
Remove the quotes. Use intval/doubleval if the input is a string as in $fstrto = intval($fstrto);.
$fstrto = 10;
$cstrto = 7;
if($status == 'N')
{
$cond = $fstrto <= $cstrto;
}
else
{
$cond = $fstrto >= $cstrto;
}
if($cond)
{
echo "Success";
}
Why it works: $cond is being assigned the value of a boolean expression, the values of which can be true or false. if($cond) just checks whether $cond is true or false
what is need to do is when using string as a php code use
eval — Evaluate a string as PHP code
Use below code work like charm:
$fstrto = "10";
$cstrto = "7";
if($status == 'N')
{
$cond = "$fstrto <= $cstrto";
}
else
{
$cond = "$fstrto >= $cstrto";
}
if(eval("return $cond;"))
{
echo "Success";
}
IMPORTANT:
Use of eval is highly discouraged
NEVER EVER use eval with params by POST/GET without sanitize them
When is eval evil in php?
You "$fstrto <= $cstrto" is a string now a compare statement.
$fstrto = "10";
$cstrto = "7";
if( ($status == 'N' && $fstrto <= $cstrto) || ($status != 'N' && $fstrto >= $cstrto) )
{
echo "Success";
}
Potentially turn it into a function that funnels into a switch statement like so:
function evaluateCondition($status, $a, $b) {
switch ($status) {
case 'Y':
return $a >= $b;
break;
case 'N':
return $a <= $b;
break;
default:
// Error Log. Unknown Status.
}
}
Any future addition can be appended onto the switch statement as necessary, if it gets more convoluted have each case return a separate function() to improve readability.
In terms of the current version you could use it like so:
$result = evaluateCondition('Y', 5, 6);
var_dump($result); // bool(false)
Hope that helps.
$fstrto = "10";
$cstrto = "7";
$cond = false;
if($status == 'N')
{
if($fstrto <= $cstrto){
$cond = true;
}
}
else
{
if($fstrto >= $cstrto){
$cond = false;
}
}
if($cond)
{
echo "Success";
}
How to execute php if condition once time only and didn't check it again, i put if condition in for loop and i want to check it one time only:
<?php
for($x=0;$x<3;$x++){
if($x == $x){
echo "";
}
else{
echo "hidden";
}
}
I need to execute first if one time only in for loop
I need to execute first if one time only in for loop. Well that's not how you do it, you need to compare with a variable and upon success just use break to come out of the loop. Something like:
<?php
$y = 0;
for($x=0; $x<3; $x++){
if($x === $y){
echo "X is Equal to Y";
break;
}
else {echo "hidden";}
}
echo "<br>". "You're outside the loop!";
?>
Set a flag, if flag is true don't execute if condition.
<?php
$flag = 0;
for($x=0;$x<3;$x++) {
if($x == $x && $flag == 0){
echo "";
$flag = 1;
}
else{
echo "hidden";
}
}
Lets say I have a variable $a that holds an integer between 0 to 10. $a needs to be not empty/not null to run a code. It works when the integer is between 1 to 10, but when it is 0, it treats $a as empty.
$a = 5;
if (!empty($a))
{ echo "not empty"; }
else
{ echo "empty";}
This this case it echoes "not empty".
$a = 0;
if (!empty($a))
{ echo "not empty"; }
else
{ echo "empty";}
But in this case it echoes "empty".
Is there a way to differentiate between 0 and an empty variable?
check for null an a string length of 0
if(null === $a || strlen($) === 0) {
}
Instead of empty you could use isset: http://fr2.php.net/isset
if (isset($a))
{ echo "not empty"; }
else
{ echo "empty";}
You can use the strict equality operator === to test for zero:
$a = 0;
$isZero = $a === 0; // $isZero is true
There is a difference between EMPTY and NULL. For $a = 0, $a is EMPTY but not NULL. So you can use isset($a) to check if $a is NULL or not.
if (isset($a)) {
echo 'not null';
} else {
echo 'is null';
}
I am trying to add a condition dynamically in the if condition . But it is not working . Please help me to fix the issue.
I am trying a code like this
$day_difference = "some integer value";
if(sheduled_time == 'evening'){
$condition = '>';
}else{
$condition = '==';
}
then
if($day_difference.$condition. 0){
echo "something";
}else{
echo "h";
}
An alternative to gerald's solution; I would suggest that you use a function that validates the inputs using a switch-case operation:
function evaluate ($var1, $operator, $var2)
{
switch $operator
{
case: '<': return ($var1 < $var2);
case: '>': return ($var1 > $var2);
case: '==': return ($var1 == $var2);
}
return null;
}
What you need is the eval() method.
I.e.
$var1 = 11;
$var2 = 110;
$cond1 = '$var1 > $var2';
$cond2 = '$var1 < $var2';
if(eval("return $cond1;")){
echo $cond1;
}
if(eval("return $cond2;")){
echo $cond2;
}
As justly noted beneath, you should exercise the necessary precautions when using this method!
This is not the way to do this.
Just define a function which returns true if the desired conditions are met.
For example, we can define the function decide which receives two arguments, $day_difference and $scheduled_time:
function decide($day_difference, $scheduled_time)
{
if($scheduled_time == 'evening')
{
return $day_difference > 0;
}
else
{
return $day_difference == 0;
}
}
And use it like so:
if( decide($day_difference, $scheduled_time) )
{
echo "something";
}
else
{
echo "h";
}
according to your requirements this can be done using the PHP eval() function which i don't recommend using it only when necessary.
you can check When is eval evil in php?
you can use the below script instead:
if( $sheduled_time == 'evening' && $diff > 0 )
{
echo "This is the Evening and the Difference is Positive";
}
else if($diff == 0)
{
echo "This is not evening";
}
Thankyou for helping me solve my question
I solved this in another way
$day_difference = "some integer value";
$var1 = false ;
if($sheduled_time == 'evening_before'){
if($day_difference > 0 ){
$var1 = true ;
}
}else{
if($day_difference == 0 ){
$var1 = true ;
}
}
if($var1 === true){
echo "something";
}else{
echo "h";
}