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<?php $tests = [ 'Test', 'test', 'test1', '1test', 'test!' ]; foreach ($tests as $test) { echo "$test: " , (ctype_lower($test) ? 'true' : 'false') , "\n"; }
Output for 7.1.25 - 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 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
Test: false test: true test1: false 1test: false test!: false

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