How to write array in php

By Arashijar | 03.05.2021

how to write array in php


PHP Forms PHP Form Handling PHP Form Validation PHP Form Required PHP Form URL/E-mail PHP Form Complete PHP Advanced PHP Date and Time PHP Include PHP File Handling PHP File Open/Read PHP File Create/Write PHP File Upload PHP Cookies PHP Sessions PHP Filters PHP Filters Advanced PHP Callback Functions PHP JSON PHP Exceptions PHP OOP. array_combine — Creates an array by using one array for keys and another for its values array_count_values — Counts all the values of an array array_diff_assoc — Computes the difference of arrays with additional index check.

Join Stack Overflow to learn, share knowledge, and build your how to write array in php. Connect and share knowledge within a single location that is structured and easy to search. My question is if I miss a way to avoid error handling and yet work with a single btree lookup?

The array caches the results of a complex calculation - to complex to be done in real time. Out of billions of possible values, only millions yied a valid result. Initial load time does not matter. If the key is not found, it simply means that this specific calue will not return a valid result. How to write array in php there is no way found to get how to remove insect in ear value with a single lookup and without error handling, I hve trouble accepting a single answer.

Instead I upvoted all the great contributions. There was a lot of confusion on how PHP handles arrays. If you check the sourcecode, you will see that all arrays are balanced trees. Since PHP 7 you can accomplish this with the null coalesce operator :. First of all, arrays are not implemented as a B-tree, it's a hash table; an array of buckets indexed via a hash functioneach with a linked list of actual values in case of hash collisions.

This means that lookup times depend on how well the hash function has "spread" the values across the buckets, i. This introduces a function call and is therefore much slower than the optimized isset. How much? Besides not having the side effect of references, it's also faster in runtime, even when performing the lookup twice.

You could look into dividing your arrays into smaller pieces as one way to mitigate long lookup times. It would remove the need of a loop to access the data. Something like that :. First, re-organize the data for performance by saving a new array where the data is sorted by the keys, but the new array contains a regular numeric index. Once that is done it should be quick to find the key using a Binary Search.

Later you can use a function like this. I how to write array in php promise it's faster. Only an octree would be quicker, but the time to build the octree might cancel out the search performance I've experienced that before. It depends on how much searching in the data you have to do. With both of these methods, it modifies the error reporting setting for PHP, but PHP's error handler will still be called.

I prefer using the isset function instead of escaping the error. I made a function to check the key exists and if not returns a default value, in the case of nested arrays you just need to add the other keys in order:. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Learn more. Asked 7 years, 11 months ago. Active 1 year, 6 months ago. Viewed 59k times. The key can be undefinied: In that case it shall be legal to return NULL without any error message: Array key exists: return value of element. Array key does not exist: return null. That effectively doubles the runtime. The secondone uses the error supression operator, and thus creates a massive overhead on that line.

To answer some questions: The array caches the results of a complex calculation - to complex to be done in real time. Conclusion As there is no way found to get what eyesight is considered legally blind value with a single lookup and without error handling, I hve trouble accepting how to write array in php single answer.

Zsolt Szilagyi. Zsolt Szilagyi Zsolt Szilagyi 3, 4 4 gold badges 22 22 silver badges 40 40 bronze badges. I updated the question to clarify: If key exists, return value, otherwise return null. Value of existent keys will never be null. Quickhash might be good for how to write array in php case. You may need to rethink your strategy and involve some type of pagination or how to tell how old your rabbit is to segment the data.

Mike, Mathew, I updated my question to answer yours. Of course native C is faster than PHP. I am simply unwilling to spend a month writing code I can write over night in PHP. Show 11 more comments. Active Oldest Votes. I was skeptical about this approach, so I generated a random array of about keys in the range of , and ran through the array fromI tried your methoed with reference, a method how to write array in php reference, but still how to take away period pains auxiliary variable, and a simple approach without either auxiliary variable or reference.

Your reference approach took more than twice as long as the other how to write array in php. The naive approach was marginally faster than the auxiliary variable approach. It also mentions that without it, the first solution given by OP is likely the fastest. In what way does your approach modify the array? ZsoltSzilagy When you create a reference on a non-existent variable, PHP creates the necessary structures to make it a valid reference; in this case, it creates an array entry with value null.

Still, however, my tests imply that this doesn't improve the performance after all. Even after having run through every item in the array once, the lookup time is still worse.

My tests could be bad. Sean Bright k 17 17 gold badges silver badges bronze badges. Even with error reporting off, the errors are still generated.

Correct Jack. Add a comment. There are two typical approaches to this. Define defaults for an undefined key. Check for undefined key. Here is how to perform the first and as little code as possible. Reactgular Reactgular Thank you. The second version with the ternary operator is a double-lookup like in my first snippet.

The first version is exciting, but I have little hope: It temporaly creates a copy of a huge array, and while there is only one btree lookup, there is a complete temporary array to be balanced. Runtime raises from 2log n to 2n. Do you have the option to re-organize this data for performance?

An octree lookup would be more efficient than a linear search. You could group by the first letter of each key, and then by the second letter and so on. Great approach! PHP internally handles arrays as fully balanced trees. Do you have experience on that comparison?

The only way PHP could how to find rate of interest for loans faster is if the keys are sorted internally, and an optimized lookup is used to find a key. I've never read anything that says PHP uses optimized indexes for array keys. Aralicia Aralicia 5 5 silver badges 14 14 bronze badges. Nice approach. This part will be time consuming, but only done once.

Ivan Babic Ivan Babic 11 2 2 bronze badges. Hey, that's a nice approach form the usability perspective, but performancewise it's actually worse than the alternatives. The function call implicitely creates an array, the foreach makes a copy of it, the first line duplicates a variable etc. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.

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To answer some questions:

pg_fetch_array() returns an array that corresponds to the fetched row (record). pg_fetch_array() is an extended version of pg_fetch_row().In addition to storing the data in the numeric indices (field number) to the result array, it can also store the data using associative indices (field name). php /*Do some PHP calculation or something*/?> Means: You can open a PHP tag with php, now add your PHP code, then close the tag with?> and then write your html code. When needed to add more PHP, just open another PHP tag with php. I was skeptical about this approach, so I generated a random array of about keys in the range of ,, and ran through the array from ,

In addition to storing the data in the numeric indices field number to the result array, it can also store the data using associative indices field name. It stores both indices by default. Row number in result to fetch. Rows are numbered from 0 upwards. If omitted or null , the next row is fetched. An optional parameter that controls how the returned array is indexed.

An array indexed numerically beginning with 0 or associatively indexed by field name , or both. Each value in the array is represented as a string. Database NULL values are returned as null. Submit a Pull Request Report a Bug. Return Values An array indexed numerically beginning with 0 or associatively indexed by field name , or both. If you specify this field result type , include no quotes around it or you won't get any data, not even an error.

As of PHP 4. Timesaver Be aware of the fact that keys in array returned by this function are well, at least as of 4. So don't be surprised if you get unexpected results. Double check SQL column names and the key names. Hopefully most people realize this on their own, but the examples below where people tried to get creative with getting numerical or associative not both keys in the result are rather pointless.

Just because it is not really clear how to specify the result type, I poste this message. Just remember when you 'or die' to close your table s or you may get a confused look from non-internet explorer users.

I found this out through help from the mailing lists.

4 thoughts on “How to write array in php

  1. Sharisar

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