title: how to exclude the non numerical integers from a data frame in Python
body: <p>I have a data frame which comprises of datatypes integer, string, numeric etc. 
  Something like below. I want to exclude all the variables which are non-numeric. is there any automated way in Python?</p>
  
  <pre><code>'data.frame':   891 obs. of  12 variables:
   $ PassengerId: int  1 2 3 4 5 6 7 8 9 10 ...
   $ Survived   : int  0 1 1 1 0 0 0 0 1 1 ...
   $ Pclass     : int  3 1 3 1 3 3 1 3 3 2 ...
   $ Name       : Factor w/ 891 levels "Abbing, Mr. Anthony",..: 109 191 358 277 16 559 520 629 417 581 ...
   $ Sex        : Factor w/ 2 levels "female","male": 2 1 1 1 2 2 2 2 1 1 ...
   $ Age        : num  22 38 26 35 35 NA 54 2 27 14 ...
   $ SibSp      : int  1 1 0 1 0 0 0 3 0 1 ...
   $ Parch      : int  0 0 0 0 0 0 0 1 2 0 ...
   $ Ticket     : Factor w/ 681 levels "110152","110413",..: 524 597 670 50 473 276 86 396 345 133 ...
   $ Fare       : num  7.25 71.28 7.92 53.1 8.05 ...
   $ Cabin      : Factor w/ 148 levels "","A10","A14",..: 1 83 1 57 1 1 131 1 1 1 ...
   $ Embarked   : Factor w/ 4 levels "","C","Q","S": 4 2 4 4 4 3 4 4 4 2 ...
  </code></pre>
  
  <p>After exclusion of numeric variables, my dataframe should look like the below:</p>
  
  <pre><code>'data.frame':   891 obs. of  12 variables:
   $ PassengerId: int  1 2 3 4 5 6 7 8 9 10 ...
   $ Survived   : int  0 1 1 1 0 0 0 0 1 1 ...
   $ Pclass     : int  3 1 3 1 3 3 1 3 3 2 ...
   $ Age        : num  22 38 26 35 35 NA 54 2 27 14 ...
   $ SibSp      : int  1 1 0 1 0 0 0 3 0 1 ...
   $ Parch      : int  0 0 0 0 0 0 0 1 2 0 ...
   $ Fare       : num  7.25 71.28 7.92 53.1 8.05 ...
  </code></pre>