I wanted to check for matching values in multiple arrays, so I made a multi-dimensional array by pushing them into $array and then wrote this line of code:
$result = call_user_func_array('array_intersect', $array);
I am getting the result I want, but I am always getting this notice on that particular line of code:
Notice: Array to string conversion
Wondering what's causing this. Hope someone can enlighten me.
Your arrays (the first-level items inside $array) themselves contain arrays. This is unsupported by array_intersect, because it treats the array items as strings for purposes of determining equality:
Note: Two elements are considered equal if and only if (string) $elem1 === (string) $elem2.
In words: when the string representation is the same.
I can't say definitely without knowing what exactly you are trying to do, but a possible solution is to use array_uintersect instead which will allow you to specify in code how to compare items without necessarily casting them to string.
Related
I have an array (or associative array), with keys and values.
Then, when trying to read one of the keys, which IS in the array, I get an "undefined offset" notice.
I have two examples where it happened. One was "exploding" a string like "AAA|BBB|CCC", using | as the separator, then trying to read the resulting array at position 1.
var_dump() correctly shows an array having offsets 0 to 2, with the correct values. But I still get the notice.
Another example is I get an array (from an AJAX call, I json_decode it, etc), then I typed the following code:
foreach (array_keys($myDecodedArray) as $k) {
$value = $myDecodedArray[$k];
someOtherCode();
}
I had that damn notice appear when trying to read $myDecodedArray[$k], although php itself had just told me the key existed !
So, I solved that last case by going
foreach ($myDecodedArray as $k => $value) {
someOtherCode();
}
but still, this is extremely annoying, and makes no sense to me.
Any of you run into that problem before?
Do you have any information about what could cause that?
[EDIT]
Rahul Meshram's suggestion (which I upvoted in the comments) solved my second problem case.
However, the first case still happens (exploding a string into an array, then trying to access that array's values by their numeric keys).
The keys ARE numeric (gettype returns 'integer', var_dump on that key shows an integer too, with the right value), but trying to access $explodedArray[1] still results in that notice being displayed, despite $explodedArray having keys 0, 1, and 2, with associated values.
I'm trying to create a script that, based on an input a?? creates an array of all the combinations and permutations of all words containing an a and two other characters from the alphabet.
Values are such as a, ab, ba, dab, bga etc - as you may see the array contains (or should contain) a weird amount of values.
The problem is that the functions I use in the script outputs even more values with many duplicates.
And for some reason I can not create a flattened array without duplicates. I tried to use array_unique() but it doesn't work here. I tried to use explode() and implode() to flatten the result array, but no success. Even if I succeed to create a string from the values, when I try to transform this string into an array, the result is again the actual multi-dimensional array.
This drives me crazy, and as you see the code, I'm a beginner in PHP.
Any help to transform the actual multidimensional array to a flattened one without duplicates is highly appreciated. An example: actually the array contains 12168 sub-arrays, and only the string a occurs 1456 times. What I need is an array that doesn't have sub-arrays and contains each results only one time.
The PHP code is available at here
and the output is here:
Have you tried something like:
$inputString = 'a??';
$array = array();
if (strpos($inputString, 'a') !== false && !in_array($inputString, $array)) {
$array[] = $inputString;
}
echo '<pre>'; print_r($array); echo '</pre>';
What am I doing wrong with this? If I just run this:
$region = EM_Locations::get(array('orderby'=>'region_name'));
all is good. However when I add in the array_unique:
$region = EM_Locations::get(array('orderby'=>'region_name'));
$reg = array_unique($region)
It breaks and get "EM_Location could not be converted to string"
array_unique() sorts the values treated as string, two elements are
considered equal if and only if (string) $elem1 === (string) $elem2.
You can add __toString() method for the EM_Location class.
From the documentation for array_unique:
array_unique() sorts the values treated as string at first, then will
keep the first key encountered for every value, and ignore all
following keys.
This means that the values must be converted to a string for comparison, but your values appear to be of type EM_Location, which PHP can't figure out how to convert to a string.
I don't understand this array accessing syntax:
$target[$segs[count($segs)]]
Is it really possible to use variables as multidimensional array keys?
That might result in an error, if $segs is a numerical array with continuous indices only.
Meaning, it would fail for:
array("foo","bar");
but work for
array("foo", 2=>"bar");
Assuming now, that we deal with the first case, then this would work:
$target[$segs[count($segs) - 1]]
First, count($segs) - 1 will be evaluated and return a number. In this case the last index of $segs (provided it is a numerical array).
$segs[count($segs) - 1] will therefore return the last element in $segs. And whatever that value is, will be used as index for $target[...].
To sum up: It is nested array indexing and evaluated inside out.
See it in action.
Whether or not such a method is necessary depends on the problem you are trying to solve. If you don't know where you would use such nested, variable array indexing then you probably don't need it.
That syntax is fine, provided $segs is an array. It's worth noting, though, that if you're using a numerically indexed array for $segs, calling count($segs) is a non-existent key because indexing starts at zero.
$test['test'] = 'test';
if(isset($test['test']['x']))
return $test['test']['x'];
This statement returns the first character of the string in $test['test'] (in this case 't'), no matter what is specified as dimension 2.
I can't wrap my head around this behavior. I use isset() all the time. Please advise.
This happens because you're not indexing an array, you're indexing a string. Strings are not arrays in PHP. They happen to share a concept of indexes with arrays, but are really character sequences even though there is no distinct char data type in PHP.
In this case, since strings are only indexed numerically, 'x' is being converted into an integer, which results in 0. So PHP is looking for $test['test'][0]. Additionally $test is only a single-dimensional array, assuming 'test' is the only key inside.
Not really relevant to your question, but if you try something like this you should get 'e', because when converting '1x' to an integer, PHP drops anything that isn't a digit and everything after it:
// This actually returns $test['test'][1]
return $test['test']['1x'];
If you're looking for a second dimension of the $test array, $test['test'] itself needs to be an array. This will work as expected:
$test['test'] = array('x' => 'test');
if (isset($test['test']['x']))
return $test['test']['x'];
Of course, if your array potentially contains NULL values, or you want to make sure you're checking an array, use array_key_exists() instead of isset() as sirlancelot suggests. It's sliiiiightly slower, but doesn't trip on NULL values or other indexable types such as strings and objects.
Use array_key_exists for testing array keys.
It's returning 't' because all strings can be treated as arrays and 'x' will evaluate to 0 which is the first letter/value in the variable.