I am still confused those sentence after I run them, I mean how do they execute step by step, someone can give some suggestions?
print([j for i in range (10) for j in range (5)])
print([[j for i in range (10)] for j in range (5)])
print([j for i in range (10) for j in range (5) for k in range(3)])
Largely, list comprehensions are concise for loops. Sometimes they can be difficult to understand and for that reason, I would suggest converting the list comprehension into a for loop for understanding.
print([j for i in range(10) for j in range(5)])
Is the same as:
result = []
for i in range(10):
for j in range(5):
result.append(j)
The others are very similar, can you try and convert them to for loops?
Hint (2): The second one has a nested list, so you'll need to initialize another list and append that list to the main list, result.
Hint (3): The last list comprehension has another nested for loop with another variable k.
