Outline for October 22, 2020

Reading: §6
Due: Homework 2, due October 30, 2020

1. I modified homework 2, question 2, so the function isabcde(s) need not be recursive.

2. Sequences
   1. Sequences are a series of values in a particular order
   2. In Python predominantly strings and lists but also sets and tuples

3. Strings
   1. Sequence of characters (characters are strings of length 1)
   2. Strings are immutable; really important for functions

4. Basic string operations
   1. +, concatenation for strings
   2. *, repetition repeats given value
   3. len() returns length of sequence
   4. s in str returns True if s is a substring of str, False otherwise

5. Indexing, var[position]
   1. Count from 0 to len(var)−1
   2. Position can be a negative number to count from right

6. Assignment with indexing doesn’t work as strings immutable;
   x = ’hEllo’; x[1] = ’e’ produces an error

7. Slicing, var[start:end]
   1. Value at index end not included in slice
   2. If omitted, starting value defaults to 0 and ending value defaults to last index + 1
   3. Can use negative index

8. Looping over strings: for i in str

9. Example program [strstuff.py]

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

MHI 289I, Programming for Health Informatics Version of October 21, 2020 at 11:15AM

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