如何在点存在之前附加逗号一个字符？ [关闭]

I have this as a string-

$String ="A. Bird Blue B. Red Hat C. Purple Dinosaur D. Black hat E. Clean soap";

I want this -

$output="A. Bird Blue, B. Red Hat, C. Purple Dinosaur, D. Black hat, E. Clean soap";

Please help me with this.

You can try using regex.

$String ="A. Bird Blue B. Red Hat C. Purple Dinosaur D. Black hat E. Clean soap";
$regex = '/(\s[A-Z]\.)/';
$Output = preg_replace($regex, ',$1', $String);
echo $Output;

Output:

 A. Bird Blue, B. Red Hat, C. Purple Dinosaur, D. Black hat, E. Clean soap

Regex Explanation:

/(\s[A-Z]\.)/

• \s match any white space character

• [A-Z] match a single character present in the list below A-Z a single character in the range between A and Z (case sensitive)

• \. matches the character . literally

The matching is replaced by [comma + first group (\s[A-Z]\.)].