Write a function that takes a list of pairs such as [(2, 3), (4, 1), (6, 5)] and returns a list in which the pairs have been swapped, e.g. [(3, 2), (1, 4), (5, 6)]. Use a list comprehension.
Write a function diagonal() that takes an integer n and returns a diagonal matrix of dimensions n x n. Recall tha a diagonal matrix has ones along its main diagonal and zeroes everywhere else. For example, diagonal(4) will return
[ [1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1] ]
Use a nested list comprehension.
Write a function that computes the sum of two matrices A and B, represented as lists of lists. Assert that the matrices have the same dimensions. Use a nested list comprehension.
Write a
function that takes a dictionary such as { 'green' :
'zelený', 'red' : 'červený' } and
returns a corresponding dictionary in which the keys and values have
been flipped, e.g. { 'zelený' : 'green', 'červený' :
'red'} . Assume that all values in the dictionary are unique.
Use a dictionary comprehension.
The well-known UNIX utility 'grep' prints all lines in a file that contain a given string. It has the syntax
grep <string> <filename>
For example:
$ grep world ulysses Gleams that untravell'd world whose margin fades 'T is not too late to seek a newer world. $
If you include the '-i' option, it matches lines without regard to case:
$ grep -i achilles ulysses And see the great Achilles, whom we knew.
Write 'grep' in Python:
$ python3 grep.py -i achilles ulysses And see the great Achilles, whom we knew.
Solve Project Euler problem #9 (Special Pythagorean triplet).
Solve Project Euler problem #11 (Largest product in a grid). Read the grid from standard input.