foreach loop, assistance request

Posted on 16th Feb 2014 07:03 pm by admin

I would like some guidance on the usage of foreach as I try to parse through a large database and whittle down to a few select stocks. I'm currently doing this with vb, but I'm wanting to get it working in php. I think I'm just struggling with the syntax, but I'm unsure. After a week of trial and error, I've decided it's time to reach out for help.

Currently, I can connect with the db, run a simple query, and return the results to a web page. The db is made up of the past 2 weeks' stock symbols, prices, volumes. I want to go through each symbol and check against 2 conditions. If both conditions are true for that symbol, I want to put it (and the 2 weeks of data) in another db for further parsing later. So in plain english, here's what I'm trying to accomplish:

for each unique symbol,
if condition a is true on every day and
condition b is true on every day, then
write all the data for the past 2 weeks for that symbol to db_x

I'm not sure if it's the most efficient method, but I was thinking I'd loop through the db checking the conditions and meanwhile saving the data to an array, then if the conditions are true when it gets to a different symbol it runs thrrough the array and adds the data to db_x....if it gets a false anywhere along the way for a particular symbol, it clears the array and moves on to the next symbol to check it. I don't want to hard code the 2 week's (ie loop through each stock 10 times, because of holidays, some stocks do not trade every day, etc). I need to check for the symbol changing to know when it's time to make a decision on whether to add or drop the previous symbol.

I've got it loosely structured to use a while loop to cycle through the entire list:
while ($row = mysql_fetch_assoc($result)) {

Then I suppose the foreach would be used, but I'm running into complex commands that I'm needing guidance on. Is ArrayIterator current to PHP5, and if so, is this the direction I should be studying up on? Any recommendations on a good online tutorial for someone who is not well versed in programming, but can get by through dogged determination (and a little help from my friends )?

It should be noted that my array I'm iterating through (the symbols) has several associated elements (volume, closing price, high, low).

As for providing code, I really don't have anything to go by yet. I have not delved too far past "foreach ($arr as $key => $value). I'm using mysql 5 and php 5 and apache2 on an Ubuntu 9.04 machine.

Thank you,

Your Answer:

Login to answer

Other forums

Retrieving innerHTML with cURL?
Hey all (sorry I know I'm a leecher, but I soon won't be. This is my first PHP project, but not my l

file_put_contents and createimagefromjpeg
All,
I do somethings and then I have the following code:
file_put_contents('./test/'.$filename

adding 0 to numbers
Hey guys i need to create a 00001 number in a loop. Is there a better way of forcing a 5 digit numbe

Pre-Fill out a PHP form...??
This is for work actually (geek squad). We have to fill out this online php form at work over and ov

check if value exists
I have googled this for a while and I am getting lots of different results. Is there a standard meth

Sql and php order list script problems
Hi im having a few problems with trying to get the coding right on a orders list ive done (or trying

A little help needed passing hidden values to next page
I have a page that has hidden values in a form.

example
Code: <input name='signupID

user data not transferring to new page
I'm a PHP learner. After an index.php page, the user goes to a login.php page. Both pages seem to

Calander layout
Hi i know this sounds like a simple question but i cant find the answer to it anywhere i have added

disable all input buttons
Hello Friends,

suppose i do have a file ( file.php ) has a submit button

Code: [Sele