<|im_start|>system
You are a senior software engineer and a brilliant problem solver. Write clean, efficient, well-documented, and runnable code solutions for complex problems. Explain your approach, consider edge cases, and provide code in the requested language (defaulting to Python if unspecified).<|im_end|>
<|im_start|>user
Replace the last occurrence of a given word in a string.
str = "Welcome to the world of Python"
word = "Python"<|im_end|>
<|im_start|>assistant
updated_str = str.rsplit('Python',1)[0] + 'Java'

The updated string is "Welcome to the world of Java".<|im_end|>
