php check array empty
Check whether an array is empty [duplicate]
I have the following code
12 Answers 12
There are two elements in array and this definitely doesn’t mean that array is empty. As a quick workaround you can do following:
Otherwise in your particular case empty() construct will always return true if there is at least one element even with «empty» value.
You can also check it by doing.
Try to check it’s size with sizeof if 0 no elements.
PHP’s built-in empty() function checks to see whether the variable is empty, null, false, or a representation of zero. It doesn’t return true just because the value associated with an array entry is false, in this case the array has actual elements in it and that’s all that’s evaluated.
If you’d like to check whether a particular error condition is set to true in an associative array, you can use the array_keys() function to filter the keys that have their value set to true.
You can then use the empty() function to check whether this array is empty, simultaneously telling you whether there are errors and also which errors have occurred.
array with zero elements converts to false
However, empty($error) still returns true, even though nothing is set.
That’s not how empty() works. According to the manual, it will return true on an empty array only. Anything else wouldn’t make sense.
How do I check if array value is empty?
Here is my array ouput
How do I know the [3] => is empty?
My out put showing all is not empty. What is correct way to check is empty?
8 Answers 8
It works as expected, third one is empty
Maybe try to trim its value, just in case that third value would be just a space.
You can check for an empty array by using the following:
You can use array_diff() and array_diff_key() :
array_diff() extracts all items which are not the same (therefore leaving out the blanks), array_diff_key gives back the differences to the original array.
Here is a simple solution to check an array for empty key values and return the key.
To check if array contains an empty key value. Try this.
An other solution:
im using in my project like this for check this array
im posting form data like this array(‘username’ => ‘john’,’surname’ => ‘sins’);
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How to check whether an array is empty using PHP?
21 Answers 21
If you just need to check if there are ANY elements in the array
If you need to clean out empty values before checking (generally done to prevent explode ing weird strings):
An empty array is falsey in PHP, so you don’t even need to use empty() as others have suggested.
Some decent answers, but just thought I’d expand a bit to explain more clearly when PHP determines if an array is empty.
An array with a key (or keys) will be determined as NOT empty by PHP.
As array values need keys to exist, having values or not in an array doesn’t determine if it’s empty, only if there are no keys (AND therefore no values).
So checking an array with empty() doesn’t simply tell you if you have values or not, it tells you if the array is empty, and keys are part of an array.
So consider how you are producing your array before deciding which checking method to use.
EG An array will have keys when a user submits your HTML form when each form field has an array name (ie name=»array[]» ).
A non empty array will be produced for each field as there will be auto incremented key values for each form field’s array.
Take these arrays for example:
If you echo out the array keys and values for the above arrays, you get the following:
ARRAY ONE:
[UserKeyA] => [UserValueA]
[UserKeyB] => [UserValueB]
ARRAY TWO:
[0] => [UserValue01]
[1] => [UserValue02]
And testing the above arrays with empty() returns the following results:
ARRAY TWO:
$ArrayTwo is not empty
ARRAY THREE:
$ArrayThree is not empty
An array will always be empty when you assign an array but don’t use it thereafter, such as:
This will be empty, ie PHP will return TRUE when using if empty() on the above.
In this case, you can loop the array in a foreach, testing if each key has a value. This is a good method if you need to run through the array anyway, perhaps checking the keys or sanitising data.
However it is not the best method if you simply need to know «if values exist» returns TRUE or FALSE. There are various methods to determine if an array has any values when it’s know it will have keys. A function or class might be the best approach, but as always it depends on your environment and exact requirements, as well as other things such as what you currently do with the array (if anything).
Here’s an approach which uses very little code to check if an array has values:
Using array_filter() :
Iterates over each value in the array passing them to the callback function. If the callback function returns true, the current value from array is returned into the result array. Array keys are preserved.
Running array_filter() on all three example arrays (created in the first code block in this answer) results in the following:
ARRAY TWO:
$arraytwo is not empty
ARRAY THREE:
$arraythree is empty
So when there are no values, whether there are keys or not, using array_filter() to create a new array and then check if the new array is empty shows if there were any values in the original array.
It is not ideal and a bit messy, but if you have a huge array and don’t need to loop through it for any other reason, then this is the simplest in terms of code needed.
I’m not experienced in checking overheads, but it would be good to know the differences between using array_filter() and foreach checking if a value is found.
Obviously benchmark would need to be on various parameters, on small and large arrays and when there are values and not etc.
If you’d like to exclude the false or empty rows (such as 0 => » ), where using empty() will fail, you can try:
array_filter() : If no callback is supplied, all entries of array equal to FALSE (see converting to boolean) will be removed.
If you’d like to remove all NULL, FALSE and empty strings ( » ), but leave zero values ( 0 ), you can use strlen as a callback, e.g.:
If you want to ascertain whether the variable you are testing is actually explicitly an empty array, you could use something like this:
I ran the benchmark included at the end of the post. To compare the methods:
and got the following results
The difference between empty and casting to a boolean are insignificant. I’ve run this test multiple times and they appear to be essentially equivalent. The contents of the arrays do not seem to play a significant role. The two produce the opposite results but the logical negation is barely enough to push casting to winning most of the time so I personally prefer empty for the sake of legibility in either case.
Why has no one said this answer:
if you are to check the array content you may use:
In my opinion the simplest way for an indexed array would be simply:
An ‘if’ condition on the array would evaluate to true if the array is not empty and false if the array is empty. This is not applicable to associative arrays.
But note that if the array has a large number of keys, this code will spend much time counting them, as compared to the other answers here.
You can use array_filter() which works great for all situations:
Making the most appropriate decision requires knowing the quality of your data and what processes are to follow.
Might your string value contain a 0 that you want to deem true/valid/non-empty? If so, then you only need to check if the column value has length.
Why have I gone to such length to explain this very basic task?
best way to check a empty array?
How can I check an array recursively for empty content like this example:
The array is not empty but there is no content. How can I check this with a simple function?
11 Answers 11
If your array is only one level deep you can also do:
Works in most cases 🙂
Solution with array_walk_recursive:
Assuming the array will always contain the same type of data:
Short circuiting included.
Here’s my version. Once it finds a non-empty string in an array, it stops. Plus it properly checks on empty strings, so that a 0 (zero) is not considered an empty string (which would be if you used empty() function). By the way even using this function just for strings has proven invaluable over the years.
If anyone stumbles on this question and needs to check if the entire array is NULL, meaning that each pair in the array is equal to null, this is a handy function. You could very easily modify it to return true if any variable returns NULL as well. I needed this for a certain web form where it updated users data and it was possible for it to come through completely blank, therefor not needing to do any SQL.
Returns TRUE if passed a variable other than an array, or if any of the nested arrays contains a value (including falsy values!). Returns FALSE otherwise. Short circuits.
Here’s a good utility function that will return true (1) if the array is empty, or false (0) if not:
For example, given a multidimensional array:
View this code interactively at: http://codepad.org/l2C0Efab
I needed a function to filter an array recursively for non empty values.
Here is my recursive function:
array_slice($result, 0) has the effect that numeric indices will be rearranged (0..length-1).
Check if all items of array are empty
I’m beginner in the PHP programming. Please can somebody suggest me any trick? How could I shorten this script with any cycle function?
I think that it is possible to make it somehow. But I don’t know how.
6 Answers 6
you can use array_filter built in function,
This simple answer is tailored to user’s example question (it does not take into account arrays whose values are arrays/objects etc).
You should do that check before you access any Key in the POST array.
Required no loop at all, that foreach is just used to output missing keys, not to do the check
Basically you create a function which will determine the length of an array element and return it’s length.
You then map this function to all all elements and then sum it.
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