title: I need to filter the column from the beginning of a sentence
body: <p>In my code, I can filter a column from exact texts, and it works without problems. However, it is necessary to filter another column with the beginning of a sentence.
  The phrases in this column are:
  A_2020.092222
  A_2020.090787
  B_2020.983898
  B_2020.209308
  So, I need to receive everything that starts with A_20 and B_20.</p>
  
  <p>Thanks in advance</p>
  
  <p>My code:</p>
  
  <pre><code>from bs4 import BeautifulSoup
  import pandas as pd
  import zipfile, urllib.request, shutil, time, csv, datetime, os, sys, os.path
  
  
  #location
  dt = datetime.datetime.now()
  file_csv = "/home/Downloads/source.CSV"
  file_csv_new = "/var/www/html/Data/Test.csv"
  
  #open CSV
  with open(file_csv, 'r', encoding='CP1251') as file:
   reader = csv.reader(file, delimiter=';')
   data = list(reader)
  
  #list to dataframe
  df = pd.DataFrame(data)
  
  #filter UF
  df = df.loc[df[9].isin(['PR','SC','RS'])]
  
  #filter key
  # A_ &amp; B_
  df = df.loc[df[35].isin(['A_20','B_20'])]
  
  #print (df)
  #Empty DataFrame
  #Columns: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, ...]
  #Index: []
  
  #[0 rows x 119 columns]```
  </code></pre>