title: How to convert a date
body: <p>I have a csv file and I import that file into anaconda. The result gave me a table with 3 columns for the date (year, month, day) and I want to turn these  columns into only one. How can I do ? Secondly, how can I associate these dates to a weekday value</p>
  
  <p>as an example, I have 1969, 01, 01 separate into 3 columns and I want a new colum with 1969-01-01. After that I want a new column saying 1969-01-01 is 'wednesday'</p>
  
  <p>see my code</p>
  
  <pre><code>import pandas as pd
  df = pd.read_csv("birthday_data.csv")
  cols = ['year','month','day']
  df['datetime'] = pd.to_datetime(df[cols])
  df['name'] = df['datetime'].dt.weekday_name
  df = df.drop(cols, axis=1)
  </code></pre>