title: How to convert list to time series in R?
body: <p>I have imported my text file like this</p>
  
  <pre><code>z&lt;-read.table("o8192",header=FALSE,as.is=TRUE);
  </code></pre>
  
  <p>But I encounter problems on the next step</p>
  
  <pre><code>spec.mtm(z,nw=4.0, k=7, nFFT="default", taper=c("dpss"))
  Warning message:
  In spec.mtm(z, nw = 4, k = 7, nFFT = "default", taper = c("dpss")) :
    Time series is not a ts object and deltat is not set. Frequency array and axes may be incorrect.
  
  &gt; head(z)
           V1
  1 -938.5499
  2 -938.5424
  3 -938.5349
  4 -938.5236
  5 -938.5236
  6 -938.5123
  </code></pre>
  
  <p>z has 8192 lines.</p>
  
  <p>How to convert list to ts?</p>