src/Primitive/String/String.php
public function offsetSet($offset, $value)
    {
        if (is_null($offset))
        {
            $this->string = $this->string.$value;
        }

        if ($this->offsetExists($offset))
        {
            $this->string = (string) $this->chars()->set($offset, $this->retrieveValue($value))->join();
        }
    }
public function offsetSet($offset, $value)
    {
        if (is_null($offset))
        {
            $this->string = $this->string.$value;
        }

        if ($this->offsetExists($offset))
        {
            $this->string = (string) $this->chars()->set($offset, $this->retrieveValue($value))->join();
        }
    }
(PHP 5 &gt;= 5.0.0)
Offset to set. Sets chars to given index.
@link http://php.net/manual/en/arrayaccess.offsetset.php
@param mixed $offset
The offset to assign the value to.
@param mixed $value
The value to set.

@return void