title: Can corr.test be used for any dataframe?
body: <p>I am trying to find get correlations and p-values between variables in a dataframe (<code>df1</code>) using corr.test in the psych package.  The variables in the  dataframe are all integers and there is no NAs.  But when I run the <code>corr.test(df1)</code>, there is always a error message.  </p>
  
  <pre><code>Error in data.frame(lower = lower, r = r[lower.tri(r)], upper = upper,  : 
    arguments imply differing number of rows: 0, 28
  </code></pre>
  
  <p>I tried to run the example (<code>corr.test(sat.act)</code>) in the psych package and there is no error.
  I am new to R, can someone tell me what is wrong with the dataframe. </p>
  
  <pre><code>&gt; head(df1)
    S1.pre S2.pre S1.post S2.post V1.pre V2.pre V1.post V2.post
  1     21     31      25      35      7      1      19       4
  2     15     26      21      29     13     11      16      14
  3     18     27      23      31      8      2       3       3
  4     17     31      18      39     13     11      15      14
  5     15     26      16      29     26     15      32      20
  6     17     28      16      28      2      4       2       7
  
  &gt; dput(head(df1))
  structure(list(S1.pre = c(21L, 15L, 18L, 17L, 15L, 17L), S2.pre = c(31L, 
  26L, 27L, 31L, 26L, 28L), S1.post = c(25L, 21L, 23L, 18L, 16L, 
  16L), S2.post = c(35L, 29L, 31L, 39L, 29L, 28L), V1.pre = c(7L, 
  13L, 8L, 13L, 26L, 2L), V2.pre = c(1L, 11L, 2L, 11L, 15L, 4L), 
  V1.post = c(19L, 16L, 3L, 15L, 32L, 2L), V2.post = c(4L, 
  14L, 3L, 14L, 20L, 7L)), .Names = c("S1.pre", "S2.pre", "S1.post", 
  "S2.post", "V1.pre", "V2.pre", "V1.post", "V2.post"), row.names = c(NA, 
  6L), class = "data.frame")
  
  &gt; sapply(df1, class)
  S1.pre    S2.pre   S1.post   S2.post    V1.pre    V2.pre   V1.post   V2.post 
  "integer" "integer" "integer" "integer" "integer" "integer" "integer" "integer" 
  </code></pre>