title: An Error from SVM in R
body: <p>I am new to R and try to retrieve data from a text, and then apply it in SVM for classification. Here is the code:</p>
  
  <pre><code>train&lt;-read.table("training.txt")
  train[which(train=="?",arr.ind=TRUE)]&lt;-NA
  train=unique(train)
  y=train[,length(train)]
  
  classifier&lt;-svm(y~.,data=train[,-length(train)],scale=F)
  classifier&lt;-svm(x=train[,-length(train)],y=factor(y),scale=F)
  </code></pre>
  
  <p>I try the 2 different ways to invoke svm, for the 1st one <code>(svm(y~.,data=train[,-length(train)],scale=F))</code> seems ok, but the 2nd one has problems, it reported:</p>
  
  <pre><code>Error in svm.default(x = train[, length(train)], y = factor(y), scale = F) : 
    NA/NaN/Inf in foreign function call (arg 1)
  In addition: Warning message:
  In svm.default(x = train[, length(train)], y = factor(y), scale = F) :
    NAs introduced by coercion
  </code></pre>
  
  <p>Here is a sample of the <code>training.txt</code>, the last column is the target</p>
  
  <pre><code>39,State-gov,77516,Bachelors,13,Never-married,Adm-clerical,Not-in-family,White,Male,2174,0,40,United-States,0
  50,Self-emp-not-inc,83311,Bachelors,13,Married-civ-spouse,Exec-managerial,Husband,White,Male,0,0,13,United-States,0
  38,Private,215646,HS-grad,9,Divorced,Handlers-cleaners,Not-in-family,White,Male,0,0,40,United-States,0
  53,Private,234721,11th,7,Married-civ-spouse,Handlers-cleaners,Husband,Black,Male,0,0,40,United-States,0
  28,Private,338409,Bachelors,13,Married-civ-spouse,Prof-specialty,Wife,Black,Female,0,0,40,Cuba,0
  37,Private,284582,Masters,14,Married-civ-spouse,Exec-managerial,Wife,White,Female,0,0,40,United-States,0
  49,Private,160187,9th,5,Married-spouse-absent,Other-service,Not-in-family,Black,Female,0,0,16,Jamaica,0
  52,Self-emp-not-inc,209642,HS-grad,9,Married-civ-spouse,Exec-managerial,Husband,White,Male,0,0,45,United-States,1
  31,Private,45781,Masters,14,Never-married,Prof-specialty,Not-in-family,White,Female,14084,0,50,United-States,1
  42,Private,159449,Bachelors,13,Married-civ-spouse,Exec-managerial,Husband,White,Male,5178,0,40,United-States,1
  37,Private,280464,Some-college,10,Married-civ-spouse,Exec-managerial,Husband,Black,Male,0,0,80,United-States,1
  30,State-gov,141297,Bachelors,13,Married-civ-spouse,Prof-specialty,Husband,Asian-Pac-Islander,Male,0,0,40,India,1
  23,Private,122272,Bachelors,13,Never-married,Adm-clerical,Own-child,White,Female,0,0,30,United-States,0
  32,Private,205019,Assoc-acdm,12,Never-married,Sales,Not-in-family,Black,Male,0,0,50,United-States,0
  40,Private,121772,Assoc-voc,11,Married-civ-spouse,Craft-repair,Husband,Asian-Pac-Islander,Male,0,0,40,NA,1
  </code></pre>
  
  <p>Any idea about it? thanks in advance!</p>