Join Mark Niemann-Ross for an in-depth discussion in this video Stepping across the image, part of Code Clinic: R (2015).
- Line 49 begins a for statement.…And the first thing that it's doing…is defining the stepSize as 100,…which is what 49 does.…And I'll see that in a second here.…But first of all, let's take a look at role 50…as well as line 53.…What this is going to be doing is…stepping through haystack pixel by pixel…and comparing needle with the values in haystack.…It will do a cross correlation function…and I'll show you that here in a second.…But essentially line 50 is a for loop…that says for row index step through…the image from left to right.…
For 53, for each row step through the columns.…So it's gonna go row one, column 1, column 2, column 3.…Actually row one, column 100, column 200, column 300.…As you can see for example in line 52 or 55,…the step index for the for loop is set…to 100 because of stepSize.…Let's scroll on down a little bit.…And we're looking at 58.…
And what this is saying now is…that we're bringing out haystack.red.…We're only bringing in the rowIndex and columnIndex,…it's a small sub-segment of the image that we're pulling.…
Mark introduces challenges and then provides an overview of his solutions in R. Challenges include topics such as statistical analysis, searching directories for images, and accessing peripheral devices.
Skill Level Intermediate
Q: R Studio tells me that it can't find files I expect to be available. Where can I find them?
A: Use the setwd() command to set the working directory to match the folder you're working in.
Q: I am unable to access the Lake Pend Oreille data from outside the U.S.
A: A static copy of this data is provided here for lynda.com members outside of the U.S.
1. Problem One: Statistical Analysis
2. Problem Two: Image Analysis
3. Problem Three: Eight Queens
4. Accessing Peripherals
5. Recursion and Directories
Walking the directory sort code10m 56s
6. Building the Web
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