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<?php $str = preg_replace('/(\w)(.)?/e', "strtoupper('$1').strtolower('$2')", 'test example.Hello World'); echo $str; ?>
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
Warning: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead in /in/HlpER on line 2
Output for 5.5.24 - 5.5.35, 5.6.7 - 5.6.28
Deprecated: preg_replace(): The /e modifier is deprecated, use preg_replace_callback instead in /in/HlpER on line 2 TeSt ExAmPlE.HeLlO WoRlD
Output for 5.4.0 - 5.4.45
TeSt ExAmPlE.HeLlO WoRlD

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