title: Issues deleting discrete vals from transformed sparse vector list using regex in python
body: <p>I'm trying to remove all values with index vals 1, 2, and 3, from a string list like
  ['1:1', '2:100.0', '3:100.0',...]. The data is in sparse vector format and was loaded as a pandas dataframe. I used an online regex tester to match the first three positions of this list with success.</p>
  
  <p>But as it exists in my program, the same regex doesn't work. On running:</p>
  
  <pre><code>data = pd.read_csv("c:\data.csv")
  
  for index, row in data.itterrows():
      line = parseline(row)
  
  def parseline(line):
      line = line.values.flatten() # data like: ['1:1 2:100.0 3:100.0...']
      stringLine = listToString(line) # data like: 1:1 2:100.0 3:100.0... 
      splitLine = stringLine.split(" ") # data like: ['1:1', '2:100.0', '3:100.0',...]
  
      remove = re.findall(r"'1:1'|'[2,3]:\d+.\d+'")
      splitLine.remove(remove)
      print(splitLine)
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>TypeError: findall() missing 1 required positional argument: 'string'
  </code></pre>
  
  <p>Does anyone have any ideas? Thanks in advance.</p>