Differences

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--- r:input_output [2017/09/28 08:05] – hkimscil
+++ r:input_output [2019/09/20 10:32] (current) – [Reading from CSV Files] hkimscil
@@ Line 38: / Line 38: @@
 > source("script.R")                   # Run the script, capturing its output
 > sink()                               # Resume writing output to console</code>
+<code>cat(data, file="analysisReport.out")
+cat(results, file="analysisRepart.out", append=TRUE)
+cat(conclusion, file="analysisReport.out", append=TRUE)</code>
+Without "append=TRUE" option, the content will be **overwritten** with the succeeding content. The above method is tedious and error prone. The second line has a different filename. The below method (making connection to file with file function) is better.
 <code>con <- file("analysisReport.out", "w")
@@ Line 45: / Line 51: @@
 close(con)</code>
+"file("filename.txt", "w")" opens "filename.txt and remains open until "close(opened_variable)" function. In this case, append=TRUE option is not necessary.
 ====== Listing Files ======
 <code>list.files()</code>
@@ Line 56: / Line 63: @@
 <code>> records <- read.fwf("filename", widths=c(w1, w2, ..., wn))</code>
-<code>Fisher    R.A.      1890 1962
+<code txt fixed-width.txt>
+Fisher    R.A.      1890 1962
 Pearson   Karl      1857 1936
 Cox       Gertrude  1900 1978
 Yates     Frank     1902 1994
 Smith     Kirstine  1878 1939
 </code>
-<code>> records <- read.fwf("fixed-width.txt", widths=c(10,10,4,-1,4))
+<code>> records <- read.fwf("http://commres.net/wiki/_export/code/r/input_output?codeblock=11", widths=c(10,10,4,-1,4))
 </code>
@@ Line 76: / Line 85: @@
 Smith      Kirstine   1878 1939
 </code>
+Funky variable names (V1, V2, . . .). Use the below method with "col.names=c()" option.
+<code>> records <- read.fwf("http://commres.net/wiki/_export/code/r/input_output?codeblock=11", widths=c(10,10,4,-1,4),
++                     col.names=c("Last","First","Born","Died"))
+> records
+        Last      First Born Died
+Fisher     R.A.       1890 1962
+Pearson    Karl       1857 1936
+Cox        Gertrude   1900 1978
+Yates      Frank      1902 1994
+Smith      Kirstine   1878 1939
+</code>
 ====== Reading Tabular Data Files ======
 <code>> dfrm <- read.table("filename")</code>
@@ Line 86: / Line 106: @@
 Yates Frank 1902 1994
 Smith Kirstine 1878 1939
-.
 </code>
@@ Line 139: / Line 159: @@
 ====== Reading from CSV Files ======
-<code>> tbl <- read.csv("filename")</code>
+<code csv filename.csv>label	lbound	ubound
+low	0.000	0.674
+mid	0.674	1.640
+high	1.640	2.330
+</code>
+<code>> tbl <- read.csv("filename.csv")
+> tbl</code>
+<code>> tbl <- read.csv("filename.csv", header=FALSE)
+> tbl</code>
-<code>> tbl <- read.csv("filename", header=FALSE)</code>
+<code>> tbl <- read.csv("filename.csv", header=FALSE, sep="\t")
+> tbl</code>
 <code>> str(tbl)
@@ Line 199: / Line 230: @@
 > url <- 'http://en.wikipedia.org/wiki/World_population'
 > tbls <- readHTMLTable(url)
+</code>
+The above not working for me. :(
+<code>library(httr)
+url <- 'http://en.wikipedia.org/wiki/World_population'
+tables <- GET(url)
+tables <- readHTMLTable(rawToChar(tables$content))
 </code>