Code:
$myVar="abcd ABCD abcd";

$myVar1=str_ireplace("b", "",$myVar);

result1

acd ACD acd

$myVar2=str_replace("b", "",$myVar);

result2

acd ABCD acd
The code above prouduces the result above.

I like to replace "b" just one time.
The would-be code below doesn't work correctly, but I hope it show what I want.
Code:
would-be code

$myVar3=str_ireplace("b", "",$myVar, 1);

target result

acd ABCD abcd
How can I get my target result above?