How to convert a string array into floats in PHP

Question

I'm selecting some Strings from my SQLite DB and store them in an Array. Now I want to plot the values with the framework "Razorflow". I think it is only possible if the values of the array are floats, am I wrong?

In my DB I'm storing temperature and humidity of 12 different sensor nodes, in this form:

id|temperature|humidity|...|...

1 |     22.50C|  47.50%|...|...
..

I heared something about the floatval()-function, I also heared that this function is not made for objects like Arrays. Is there a simple solution? I'm very new to PHP :-D

LordNeo · Accepted Answer · 2017-02-21 19:29:29Z

1

Depends on how you're getting the values back from the database.

id|temperature|humidity|...|...

Sounds like a string to me, so i would first explode it into an array and then iterate the array casting floatval into every element.

What you do after that process depends on you.

EDIT:

If your query is:

$humi = $database->query((SELECT humidity FROM Measurement WHERE topic_hum='WSN9/humi'

You will get back only 1 column (humidity) and 0 or more rows depending on your database. Let's say it's only 1 for now:

$resul = mysql_query($humi,$link);
$rows = mysql_fetch_array($resul);
$myarray = explode("|", $rows["humidity"]);

This should give us an array called myarray containing X elements each with a "single" string part value. So we can iterate over it and parse it. There is also the shorthand "array_map" to iterate over an array using a callback function over each element and returning the value as an array:

$myparsedarray = array_map('floatval', $myarray)

Now you have an array with only float values (and errors maybe, check your data!)

edited Feb 21, 2017 at 19:29

answered Feb 21, 2017 at 18:37

LordNeo

1,1721 gold badge8 silver badges21 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Niclas Resse Over a year ago

I tried this command: $humi = $database->query((SELECT humidity FROM Measurement WHERE topic_hum='WSN9/humi' This query gives only one parameter back, this is also wrong. But first i want to convert the array[string] into an array[float]. Thanks for the fast response

LordNeo Over a year ago

it's ok to return only 1 column, because you're only selecting humidity. That string you need to explode it into an array, and then those elements of the array can go into the floatval. Check the links, i'll make a quick edit to put something more specific.

Collectives™ on Stack Overflow

How to convert a string array into floats in PHP

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related