What's the difference between 'eq' vs '==' in PHP?

Question

Hi,

First, I tried searching for different variations of the title I've put for this question, both in StackOverflow and google. I couldn't find a solution.

I am fairly new to php. New enough to not know the difference between using eq and == for string comparison!

I usually use == to compare strings in PHP. I am comfortable with it.

But I've seen code using eq to compare strings. And I vaguely remember someone making an observation like 'oh! I used == to compare strings. I should have used eq'

I just want to know whether using == is okay to do simple string comparisons? I am not talking about special cases, case-sensitive, substring or any fancy type of string comparison. Just checking whether apple is the same as apple.

Is == enough? or should I use eq.

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EDIT:

my mistake :( thanks a lot for clearing my 'not-well-researched' doubt! it must have been Perl. I got confused seeing the code embedded inside HTML and thought it was a different way of embedding PHP. sorry.

Answer 1

There is no eq operator in PHP. There is however == and ===.

=== is a strict comparison operator and won't do type conversion.

== will do type conversion (for example '' == 0 evaluates to true).

See Comparison Operators for a full list and Type Juggling for the rules of PHP type conversion. The only reference I could find to eq was as an argument to version_compare().

Answer 2

eq in PHP would be news to me but there is the strict comparison operator

$a === $b

check the manual for details.

Answer 3

To accompany my comments: The eq operator in Perl tests for string equality, while the == tests for numerical equality only.

Even though PHP started once as a collection of Perl scripts, I don't think, they have copied this operator and this page seems to agree.

Answer 4

PHP does't have an eq operator. You're probably thinking of perl, where eq will compare two variables as strings.

PHP has an equality operator (==) and a true equality operator (===). The true equality operator (===) will test that the expressions on each side of the operator are both equal, and of the same type. The equality operator (==) will attempt to coerce each expression to the same type, and then compare them.

//this is true
'45' == 45

//this is false
'45' === 45

There are some cases where == will make bad guesses when it comes to types, do if you know you have tow expressions of the same type, it's best to use ===.

Answer 5

The == operator checks if there's a perfect match between two variables, literals or a combination of these two programmatic entity ... but is not type safe!

If you use it to compare strings, you are comparing a string with a regular expression to find a perfect match!

But there are a lot of most powerful way to compare strings in PHP, you need only know what you are trying to accomplish .... for example: similar_text(), strcasecmp(), strcmp(), etc. Or you can compare strings by using regular expressions by calling one of the functions ereg(), eregi() with your own pattern!