# Python Itertools Tutorial – Part VI

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QuantInsti
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Get up-to-speed in this series with Part IPart II,  Part IIIPart IV, and Part V.

The combinations_with_replacement() iterator

If you had seen the output above, there were no stocks repeated in the combinations. This iterator takes care of that by listing the values repeated too.The Python code for this iterator is as follows:

# Combinations_with_replacement itertool
stocks_NYSE = [‘TSLA’, ‘MSFT’, ‘NVDA’, ‘GOOGL’ , ‘AAPL’ , ‘INTC’]
result = itertools.combinations_with_replacement(stocks_NYSE, 2)
for each in result:
print(each)

The output would is shown below:

(‘TSLA’, ‘TSLA’)
(‘TSLA’, ‘MSFT’)
(‘TSLA’, ‘NVDA’)
(‘TSLA’, ‘GOOGL’)
(‘TSLA’, ‘AAPL’)
(‘TSLA’, ‘INTC’)
(‘MSFT’, ‘MSFT’)
(‘MSFT’, ‘NVDA’)
(‘MSFT’, ‘GOOGL’)
(‘MSFT’, ‘AAPL’)
(‘MSFT’, ‘INTC’)
(‘NVDA’, ‘NVDA’)
(‘NVDA’, ‘GOOGL’)
(‘NVDA’, ‘AAPL’)
(‘NVDA’, ‘INTC’)
(‘GOOGL’, ‘GOOGL’)
(‘GOOGL’, ‘AAPL’)
(‘GOOGL’, ‘INTC’)
(‘AAPL’, ‘AAPL’)
(‘AAPL’, ‘INTC’)
(‘INTC’, ‘INTC’)

Well, these were the combinations, but what about the permutations? Let’s check it out right now.

The permutations() iterator

Recall that in permutations, the order does matter. Hence (‘TSLA’, ‘MSFT’) and (‘MSFT’, ‘TSLA’) are entirely different in permutations. Having said that, let us see the python code for this iterator.

# Permutations() itertool
stocks_NYSE = [‘TSLA’, ‘MSFT’, ‘NVDA’, ‘GOOGL’ , ‘AAPL’ , ‘INTC’]
result = itertools.permutations(stocks_NYSE, 2)
for each in result:
print(each)

The output would be as follows:

(‘TSLA’, ‘MSFT’)
(‘TSLA’, ‘NVDA’)
(‘TSLA’, ‘GOOGL’)
(‘TSLA’, ‘AAPL’)
(‘TSLA’, ‘INTC’)
(‘MSFT’, ‘TSLA’)
(‘MSFT’, ‘NVDA’)
(‘MSFT’, ‘GOOGL’)
(‘MSFT’, ‘AAPL’)
(‘MSFT’, ‘INTC’)
(‘NVDA’, ‘TSLA’)
(‘NVDA’, ‘MSFT’)
(‘NVDA’, ‘GOOGL’)
(‘NVDA’, ‘AAPL’)
(‘NVDA’, ‘INTC’)
(‘GOOGL’, ‘TSLA’)
(‘GOOGL’, ‘MSFT’)
(‘GOOGL’, ‘NVDA’)
(‘GOOGL’, ‘AAPL’)
(‘GOOGL’, ‘INTC’)
(‘AAPL’, ‘TSLA’)
(‘AAPL’, ‘MSFT’)
(‘AAPL’, ‘NVDA’)
(‘AAPL’, ‘GOOGL’)
(‘AAPL’, ‘INTC’)
(‘INTC’, ‘TSLA’)
(‘INTC’, ‘MSFT’)
(‘INTC’, ‘NVDA’)
(‘INTC’, ‘GOOGL’)
(‘INTC’, ‘AAPL’)

Visit https://www.quantinsti.com/ for ready-to-use Python functions as applied in trading and data analysis.

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