Unix Shell and Python

In [2]:
%%file ../data/animals.txt
name|species|age|weight
arun|cat|5|7.3
bob|bird|2|1.5
coco|cat|2|5.5
dumbo|elephant|23|454
elmo|dog|5|11
fido|dog|3|24.5
gumba|bird|2|2.7
Overwriting data/animals.txt

Q1. Using only the Unix shell commands, find only rows showing the 3rd, 4th and 5th heaviest animals in the file animals.txt.

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Q2. Using only the Unix shell commands, find all files in the current directory and all its subdirecotries that contain the word elephant regardless of case.

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Q3. Using only the Python standard library, find only rows showing the 3rd, 4th and 5th heaviest animals in the file animals.txt

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Q4. Using only the Python standard library, find all files in the current directory and all its sub-directories that contain the word elephant regardless of case.

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# Not graded but here is a possile solution.
for dirpath, dirnames, filenames in os.walk('.'):
    for filename in filenames:
        path = os.path.join(dirpath, filename)
        with open(path) as f:
            text = f.read()
            if 'elephant' in text.lower():
                print(path)
./Homework01.ipynb
./.ipynb_checkpoints/Homework01-checkpoint.ipynb

Q5. Starting with range(1, 20), make a list of the squares of each odd number in the following ways

  • With a for loop
  • Using a list comprehension
  • Using map and filter

The answer should be [1, 9, 25, 49, 81, 121, 169, 225, 289, 361]

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Q6. If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. (Euler problem #1)

Write a program to find the sum of all the multiples of 3 or 5 below 1000.

The answer sould be 233168.

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Q7. A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.

Write a program to find the largest palindrome made from the product of two 3-digit numbers. (Euler problem #4)

The answer should be 906609 = 913 × 993. (Thanks to Ilan Man for catching the error)

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Q8. The sum of the squares of the first ten natural numbers is,

1^2 + 2^2 + ... + 10^2 = 385

The square of the sum of the first ten natural numbers is,

\[ \begin{align}\begin{aligned}:nowrap:\\ (1 + 2 + ... + 10)^2 = 55^2 = 3025\\Hence the difference between the sum of the squares of the first ten\end{aligned}\end{align} \]

natural numbers and the square of the sum is 3025 − 385 = 2640.

Write a program to find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum. (Euler problem #6)

The answer should be 25164150.

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Q9. Problem 8: The four adjacent digits in the 1000-digit number that have the greatest product are 9 × 9 × 8 × 9 = 5832.

73167176531330624919225119674426574742355349194934
96983520312774506326239578318016984801869478851843
85861560789112949495459501737958331952853208805511
12540698747158523863050715693290963295227443043557
66896648950445244523161731856403098711121722383113
62229893423380308135336276614282806444486645238749
30358907296290491560440772390713810515859307960866
70172427121883998797908792274921901699720888093776
65727333001053367881220235421809751254540594752243
52584907711670556013604839586446706324415722155397
53697817977846174064955149290862569321978468622482
83972241375657056057490261407972968652414535100474
82166370484403199890008895243450658541227588666881
16427171479924442928230863465674813919123162824586
17866458359124566529476545682848912883142607690042
24219022671055626321111109370544217506941658960408
07198403850962455444362981230987879927244284909188
84580156166097919133875499200524063689912560717606
05886116467109405077541002256983155200055935729725
71636269561882670428252483600823257530420752963450

Write a program to find the thirteen adjacent digits in the 1000-digit number that have the greatest product. What is the value of this product? (Euler problem #8)

The answer shoud be 23514624000.

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Q10. A Pythagorean triplet is a set of three natural numbers, a < b < c, for which,

a^2 + b^2 = c^2

For example, \(3^2 + 4^2 = 9 + 16 = 25 = 5^2\)

There exists exactly one Pythagorean triplet for which a + b + c = 1000. Write a program to find the product abc. (Euler problem #9)

The answer should be (200, 375, 425, 31875000).

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