Does php include toupper and tolower functions?

Question

does php include any function like toupper and tolower

I want toupper fuction which convert ABC to abc or Abc to abc

simlary tolower shold convert ABC to abc or Abc to Abc

Answer 1

strtoupper() and strtolower().

Answer 2

echo strtolower('HELLO');
echo strtoupper('hello');

Answer 3

strtolower() and strtoupper()

Answer 4

echo strtolower('TEXT'); //text
echo strtoupper('text'); //TEXT
echo ucwords('text text'); //Text Text
echo ucfirst('text text'); //Text text
echo lcfirst('TEXT TEXT'); //tEXT TEXT