title: Python re.match: How to specific "OR" match
body: <p>Suppose I have a data file:</p>
  
  <pre><code># cat 1.txt
  #$$!#@#VM - This is VM$^#^#$^$^
  %#%$%^SAS - This is SAS&amp;%^#$^$
  !@#!@%^$^MD - This is MD!@$!@%$
  </code></pre>
  
  <p>Now I want to filter the words starting with VM and SAS (excluding MD)</p>
  
  <p>Expected results:</p>
  
  <pre><code>VM - This is VM
  SAS - This is SAS
  </code></pre>
  
  <p>I am using this code but all lines are shown.</p>
  
  <pre><code>import re
  
  f = open("1.txt", "r")
  
  for line in f:
      p = re.match(r'.+?((SAS|VM)[-a-zA-Z0-9 ]+).+?', line)
      if p:
          print (p.groups()[0])
  </code></pre>
  
  <p>In regular expression, I can use (pattern1|pattern2) to match either pattern1 or pattern2
  But in re.match, parenthesis is used for matching the pattern.</p>
  
  <p>How to specify "Either Match" in re.match() function?</p>