1String-Indexing.md

Learning Objectives:

• Subscript strings
• Combine strings and/or string literals

Trouble problem from F17: 10.6.6) Order out of (23.9%)

Problem in S18: 16.6) Order out of

Problem: Given strings assigment_1 and assignment_2, shown below, use string indexing to extract the due dates of each assignment and print the due dates, separated by a comma and a space.

assignment_1 = "Maze Game,Jan. 26,10pts"
assignment_2 = "Types,Feb. 2,10pts"

Step 0: Understanding the problem.

The idea of this problem is that you are given two strings, assignment_1 and assignment_2, each representing some details about a particular assignment. The goal is to use string indexing to extract the due date from each assignment string and print the due dates as a neatly formatted list. So the expected output is

Jan. 26, Feb. 2

Step 1: Find the indexes of each due date.

0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	22
M	a	z	e		G	a	m	e	,	J	a	n	.		2	6	,	1	0	p	t	s

We can see that the due date for assignment_1 (Jan. 26) starts at index 10 and ends at index 16. Therefore to include the entire date with string indexing we need to put

assignment_1[10:17]

because python stops at the character before the index given by the second number.

Doing the same thing for assignment_2 we can see we need to use

assignment_2[6:11]

0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
T	y	p	e	s	,	F	e	b	.		2	,	1	0	p	t	s

Step 2: Create the formatted (with a comma and space) due date string.

We know we can use the + operator to concatenate (combine) strings. So

assignment_1[10:17] + assignment_2[6:11]

gives us

Jan. 26Feb. 2

But this isn't exactly what we want. We can also concatenate string literals using the + operator. String literals are any string values in quotation marks. So assignment_1 is a variable, while "Maze Game,Jan. 26,10pts" is the string literal value we store in the variable. So with that in mind, we can use

assignment_1[10:17] + ", " + assignment_2[6:11] #Notice the space!

which gives us

Jan. 26, Feb. 2

Step 3: Print out the result.

To display the string created in Step 2, we can store it in a variable like this:

due_dates = assignment_1[10:17] + ", " + assignment_2[6:11]

then print out the variable we created:

print(due_dates)

or, we can simply print the statement from Step 2 directly by putting it in the print statement.

print(assignment_1[10:17] + ", " + assignment_2[6:11])

Solution:

print(assignment_1[10:17] + ", " + assignment_2[6:11])