We can find PHP built-in functions to accomplish common tasks. Need to reverse a string? There’s a built-in function for that!
strrev() function takes in a string as its argument and returns a string with all of the characters of the original string in reverse order.
Let’s see it in action:
echo strrev("Hello, World!"); // Prints: !dlroW ,olleH
Remember that we can use the values returned from functions directly (rather than saving them into variables). In the code above, we used
echo to print the value returned from invoking the
strrev() function with the string
"Hello, World!" as its argument.
PHP also comes with built-in functions to change the capitalization of a string. We can use the
strtolower() function to transform an argument string into all lowercase letters:
echo strtolower("HeLLo"); // Prints: hello
Built-in functions often have multiple parameters. The
str_repeat() function takes a string as its first argument and a number as its second. It returns a string containing the argument string repeated the argument number of times.
echo str_repeat("hi", 10); // Prints: hihihihihihihihihihi
In the above code we used
echo to print the value returned from invoking
10 as its arguments—
Use echo and the
strrev() function to print the following string reversed:
".pu ti peeK .taerg gniod er'uoY"
echo and the
strtolower() function to print the following string with all lowercase letters:
"SOON, tHiS WILL Look NoRmAL."
echo and the
str_repeat() function to print the string
"\nThere's no place like home.\n" three times.