Outline for January 31, 2018

Reading: §6

1. Sequences
   1. Sequences are a series of values in a particular order
   2. In Python predominantly strings and lists but also sets and tuples
2. Strings
   1. Sequence of characters (characters are strings of length 1)
   2. Strings are immutable; really important for functions
3. 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
4. Indexing, var[position]
   1. Count from 0 to len(var)−1
   2. Position can be a negative number to count from right
5. Assignment with indexing doesn’t work as strings immutable
   x = "hEllo"; x[1] = "e" produces an error
6. 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
7. Looping over strings: for i in str
8. Example program [strstuff.py]

Matt Bishop Department of Computer Science University of California at Davis Davis, CA 95616-8562 USA

Last modified: Version of January 30, 2018 at 11:26PM Winter Quarter 2018 You can get a PDF version of this