Xiaobai PHP study notes (1)

1. Main frame
<?php
?>
2. Output statement
echo/printf 
difference: printf can output more complex data types
3. Conversion of letter case
1) Convert the entire character to
uppercase: strtoupper Lowercase: strtolower
converts the first Change a character to uppercase: ucfirst Change
the first character in each short sentence of a string to uppercase: ucwords