python pandas dataframe unique values appending 'L' to data values

Question

I am running a python file as CGI which is reading a CSV into pandas dataframe. Problem is when I try to get unique values of columns that have just integer values, I get an extra appended 'L' to the data values.

Here's the code.

def Main():
  formData = cgi.FieldStorage()
  fileName = str(formData.getvalue('file'))
  field = str(formData.getvalue('field'))
  df = fileRead.readFile(fileName)
  unique = pd.unique(df[field])
  print unique.tolist()

Here's the output:

[1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 20L, 21L, 22L, 23L, 24L, 25L, 26L, 27L, 28L]

This works fine with columns that have float values or text values.

[25.9, 29.5, 27.9, 29.9, 30.9, 28.9, 84.9, 82.9, 35.9, 31.5, 31.0, 30.0, 36.9, 41.9, 40.5, 43.9, 37.5, 37.9, 44.5, 38.9, 45.8, 41.0]

BTW, fileRead is just another file which reads the CSV to dataframe.

df = pd.read_csv(path)

Answer 1

Here "L" refers to "Long". It shouldn't affect your code other than taking more memory.

example: 1L + 2 = 3L

Also, rather than doing:

unique = pd.unique(df[field])

try this

unique = df.drop_duplicates('field')