Question

Consider the following array:

$companies = array(
  'apple' => 'AAPL',
  'baxter' => 'BAX'
);

And the following strings:

apple at the beginning of string with bapple
here a string with apple in the middle
baxter baxter on first and second place mybaxters
and finally, baxter

I’m using the following loop to replace company names with their respective ticker:

foreach ($companies as $name => $ticker) {
  $tweet = str_replace(" $name", "<b>{COMPANY|$ticker}</b>", $tweet);
}

This results in

apple at the beginning of string with bapple
here a string with {COMPANY|AAPL} in the middle
baxter {COMPANY|BAX} on first and second place mybaxters
and finally, {COMPANY|BAX}

However, I would also like to cath company names at the beginning of a string:

{COMPANY|AAPL} at the beginning of string with bapple
here a string with {COMPANY|AAPL} in the middle
{COMPANY|BAX} {COMPANY|BAX} on first and second place mybaxters
and finally, {COMPANY|BAX}

But if I remove the space in " $name", words like bapple will also be replaced:

{COMPANY|AAPL} at the beginning of string with b{COMPANY|AAPL}

In other words: I want to replace all instances of company names
– when surrounded by spaces “an apple is lovely fruit”
– when at the beginning of string with a space after “apple is wonderfull”
– or when at the end of a string with leading space “so this is my apple”

This would probably require a regex, but I would need some help in writing it.

Answer 1

Try this:

foreach ($companies as $name => $ticker) {
  $tweet = preg_replace('/\b'.preg_quote($name).'\b/', "<b>{COMPANY|$ticker}</b>", $tweet);
}

The regex uses so-called word boundaries: http://www.regular-expressions.info/wordboundaries.html

The output is now:

{COMPANY|AAPL} at the beginning of string with bapple here a
string with {COMPANY|AAPL} in the middle {COMPANY|BAX}
{COMPANY|BAX} on first and second place mybaxters and finally,
{COMPANY|BAX}

If you also want to support things like apples, then take this code:

foreach ($companies as $name => $ticker) {
  $tweet = preg_replace('/\b'.preg_quote($name).'s{0,1}\b/', "<b>{COMPANY|$ticker}</b>", $tweet);

}