Wesleyan College



Exercise 6 -1 The file src/files/constants.txt5 contains a table of the values and the dimensions of some fundamental constants from physics. We want to load this table into a dictionary constants, where the keys arethe names of the constants. For example, constants[’gravitational constant’] holds the value of the gravitational constant (6.67259 · 10?11) in Newton’s law of gravitation. Make a function that reads and interprets the text in the file, and finally returns the dictionary. Filename: fundamental_constants.py.Exercise 6-5 Based on the stars data in Exercise 3.33, make a dictionary where the keys contain the names of the stars and the values correspond to the luminosity. Filename: stars_data_dict1.py.Exercise 6.17: Make a function more robust Consider the function get_base_counts(dna) from Section 6.5.3, which counts how many times A, C, G, and T appears in the string dna: Function def get_base_counts(dna): counts = {’A’: 0, ’T’: 0, ’G’: 0, ’C’: 0} for base in dna: counts[base] += 1 return counts Unfortunately, this function crashes if other letters appear in dna. Write an enhanced function get_base_counts2 which solves this problem. Test it on a string like ’ADLSTTLLD’. Filename: get_base_counts2.py.Exercise 6-6 The file src/files/human_evolution.txt6 holds information about various human species and their height, weight, and brain volume. Make a program that reads this file and stores the tabular data in a nested dictionary humans. The keys in humans correspond to the specie name (e.g., homo erectus), and the values are dictionaries with keys for height, weight, brain volume, and when (the latter for when the specie lived). For example, humans[’homo neanderthalensis’][’mass’] should equal ’55-70’. Let the program write out the humans dictionary in a nice tabular form similar to that in the file. Filename: humans.py.Exercise 6.18: Find proportion of bases inside/outside exons Consider the lactase gene as described in Sections 6.5.4 and 6.5.5. What is the proportion of base A inside and outside exons of the lactase gene? Hint. Write a function get_exons, which returns all the substrings of the exon regions concatenated. Also write a function get_introns, which returns all the substrings between the exon regions concatenated. The function get_base_frequencies from Section 6.5.3 can then be used to analyze the frequencies of bases A, C, G, and T in the two strings. Filename: prop_A_exons.py.5 , Hans Petter (2014-08-01). A Primer on Scientific Programming with Python (Texts in Computational Science and Engineering) (Page 371). Springer Berlin Heidelberg. Kindle Edition.-------------------------------------------------------------------- Final ExerciseA secret message has been hidden in the homework page for this course. To access it, you must search the HTML that creates the homework page for the course for lines containing the HTML comment character “<!—“ and the string “PHY396”. The message may be found by breaking the strings that make up these lines up into words and saving the strings that appear between successive appearances of PHY396.Write a program that accesses the homework page online and extracts the secret message. ................
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