[Tutor] please help me

[invincible patriot]

hii am stuck in these questions can someone please help me in solving and writing programme for these tasks
please help me




1 1.1 Write a Python program with a loop that prints out a sequence of numbers as follows:151311...31-1

1.2 Write a small Python program that generates the list of all pairs of characters c andits doubling 2  c, where c moves through all the letters of the string "foobar" and prints it out.The result will look like:[(’f’, ’ff’), (’o’, ’oo’), (’o’, ’oo’), (’b’, ’bb’), (’a’, ’aa’), (’r’, ’rr’)]Hint: use list comprehensions.
1.3 Write a small Python program that
1. prints out the length of the string’taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwhenuakitanatahu’
2. prints out how many different characters this string contains
3. replaces all the non-’t’ characters in above string with dots ’.’. So, if the word were’tattoo’, it would print ’t.tt..’.Hints:
(a) use a function to t-ify the string
(b) there are various ways to construct the string, either using the join method or by runninga loop accumulating substrings.
(c) check also out what happens if you apply the conversion list(s) to a string s.
2 2.1 Write a function count char(s, c) that takes a string s, and a character c and returnshow often the character c appears in the string.For example count_char("tattoo", "t") should return 3.

2.2 Write a Python function char_freqency(s)that returns a dictionary which, for eachcharacter of s as a key, stores as value how often this character appears.For example, char_frequency("tattoo") could return {’a’: 1, ’t’: 3, ’o’: 2} (the order ofkey:value pairs does not matter here).
Hint: Consider using the function count_char defined in 2.1.
2.3 Write a program that translates a given string (of arbitrary length) of DNA bases intothe RNA strand that it will produce. For this, research which DNA bases correspond to RNA basesand create a translation table (not an if...else clause!) in the Python program. [4 marks]


3 
3.1 consider the following list of base sequences:ACGTACCTTACTTACCATATCGTACCTCTTACTCATThe task consists of writing a Python program that performs a simple alignment algorithm onthese two strings and prints out this alignment in a suitable readable form. Give a brief commentexplaining the output format.Hints:1. Matching means the following: for a given sequence to be matched, your program should denotewhich bases correspond to bases in the reference sequence and which do not; in addition, markgaps where the reference sequence contains bases which are not present in the sample sequence.For a given sample sequence, your matching algorithm will attempt to match as many basesas possible to those of the reference sequence.2. This is a difficult assignment. Do not attempt it before you have solved the others.3. For this purpose, you are allowed to research and implement publicly documented versions ofthe Needleman-Wunsch algorithm or similar algorithms (however, make sure that you refer-ence them properly!). Also make sure that your program prints out the matches/mismatchesbetween the sequences. You should demonstrate at least two different alignments by usingdifferent gap penalties.Instead of following this hint, you can develop an alternative solution to the matching problem,e.g. based on the Levenshtein distance.


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