debugging exercise

Author: heike

docs/index.html

@@ -3,6 +3,7 @@
     "listing": "/index.html",
     "items": [
       "/project/report.html",
+      "/slides/09a-debugging-exercise.html",
       "/homework/08.html",
       "/homework/07.html",
       "/project/guidelines.html",

docs/listings.json

@@ -0,0 +1,134 @@
+---
+title: "Debugging Excercises"
+date: "2024-10-24"
+categories: Slides
+output: 
+  html_document: 
+    keep_md: yes
+    number_sections: yes
+---
+
+
+In the following examples, evaluate each problem using the criteria of a minimal reproducible example from [this StackOverflow post](https://stackoverflow.com/help/minimal-reproducible-example). 
+
+Specifically, address the following things: 
+
+1. Are the question and problem description complete?
+
+2. Is the issue reproducible? Does it have a description of the problem, with code that reproduces the problem? What could improve it?
+
+3. Is the example minimal? Does it include extra code or information that is not necessary?
+
+4. Does the question describe any attempted solutions?
+
+
+Then, using what you know about R and Python, try to debug the problem using the strategies in [the debugging chapter](https://srvanderplas.github.io/stat-computing-r-python/part-gen-prog/06-debugging.html). Once you are thoroughly stumped, or you believe you have solved the problem, compare your solutions to those given on StackOverflow using the link.
+
+# Why Doesn't this R function work?
+
+> I created the following function to append new strings on a vector of strings called "meals". However, when I use this function to append an string input into my "meals" vector, it does not work.
+
+```
+ add <- function(str) {
+      meals <- append(meals, as.character(str))  
+    }
+```
+
+[Link](https://stackoverflow.com/questions/39795961/why-doesnt-this-r-function-work?noredirect=1&lq=1) to original SO post. 
+
+
+
+# Function not working R
+
+> I've never programmed before and am trying to learn. I'm following that "coursera" course that I've seen other people post about — a course offered by Johns Hopkins on R programming.
+
+> Anyway, this was supposed to be my first function. Yet, it doesn't work! But when I type out all the steps individually, it runs just fine... Can anyone tell me why?
+
+```
+pollutantmean <- function(directory, pollutant, id = 1:332){
+    x<- list.files("/Users/mike******/Desktop/directory", full.names=TRUE)
+    y<- lapply(x, read.csv)
+    z<- do.call(rbind.data.frame, y[id])
+
+    mean(z$pollutant, na.rm=TRUE)
+}
+pollutantmean(specdata,nitrate,1:10)
+[1] NA
+Warning message:
+In mean.default(z$pollutant, na.rm = TRUE) :
+  argument is not numeric or logical: returning NA
+
+####
+
+x<- list.files("/Users/mike******/Desktop/specdata",full.names=TRUE)
+y<- lapply(x,read.csv)
+z<- do.call(rbind.data.frame,y[1:10])
+mean(z$nitrate,na.rm=TRUE)
+[1] 0.7976266
+```
+
+
+[Link](https://stackoverflow.com/questions/24123224/function-not-working-r/24141502)
+
+
+
+# Inexplicable error when trying to export my R notebook
+
+> Getting this error from R Markdown when trying to export my .RMD
+
+```
+"Error in filter(Gastropods, Species == "Cellana") :  object 'Species' not found Calls: <Anonymous> ... withCallingHandlers -> withVisible -> eval -> eval -> filter"
+```
+
+> However, all my plots are coming out successfully. I can clearly see in the data that the species column is there and that Cellana is a species. No spelling errors or anything.
+
+> My first 20 or so lines of code are below (between the ### symbols)
+
+
+````{r echo=FALSE}
+cat(paste(readLines("https://raw.githubusercontent.com/unl-statistics/stat850/refs/heads/main/homework/debugging_3.txt"), collapse = '\n'))
+````
+
+You can find this sample file [here](https://raw.githubusercontent.com/unl-statistics/stat850/refs/heads/main/homework/debugging_3.txt)
+
+
+[Link](https://stackoverflow.com/questions/44193367/inexplicable-error-when-trying-to-export-my-r-notebook)
+
+
+# Python if elif else statement
+
+> I'm trying to create a program with python that calculate the cost for shipping.
+
+> However, I can't run the program to where it works properly.
+
+> What ever my total is the same amount comes out as $6 for US and $8 for Canada. I can't seem to get pass that.
+
+> Example:
+
+```
+total = raw_input('What is the total amount for your online shopping?')
+country = raw_input('Shipping within the US or Canada?')
+
+if country == "US":
+    if total <= "50":
+        print "Shipping Costs $6.00"
+    elif total <= "100":
+            print "Shipping Costs $9.00"
+    elif total <= "150":
+            print "Shipping Costs $12.00"
+    else:
+        print "FREE"
+
+if country == "Canada":
+    if total <= "50":
+        print "Shipping Costs $8.00"
+    elif total <= "100":
+        print "Shipping Costs $12.00"
+    elif total <= "150":
+        print "Shipping Costs $15.00"
+    else:
+        print "FREE"
+```
+
+
+[Link](https://stackoverflow.com/questions/19371643/python-if-elif-else-statement)