pythonpandasunix-timestampdataframe

Convert unix time to readable date in pandas dataframe


I have a dataframe with unix times and prices in it. I want to convert the index column so that it shows in human readable dates.

So for instance I have date as 1349633705 in the index column but I'd want it to show as 10/07/2012 (or at least 10/07/2012 18:15).

For some context, here is the code I'm working with and what I've tried already:

import json
import urllib2
from datetime import datetime
response = urllib2.urlopen('http://blockchain.info/charts/market-price?&format=json')
data = json.load(response)   
df = DataFrame(data['values'])
df.columns = ["date","price"]
#convert dates 
df.date = df.date.apply(lambda d: datetime.strptime(d, "%Y-%m-%d"))
df.index = df.date   

As you can see I'm using df.date = df.date.apply(lambda d: datetime.strptime(d, "%Y-%m-%d")) here which doesn't work since I'm working with integers, not strings. I think I need to use datetime.date.fromtimestamp but I'm not quite sure how to apply this to the whole of df.date.

Thanks.


Solution

  • These appear to be seconds since epoch.

    In [20]: df = DataFrame(data['values'])
    
    In [21]: df.columns = ["date","price"]
    
    In [22]: df
    Out[22]: 
    <class 'pandas.core.frame.DataFrame'>
    Int64Index: 358 entries, 0 to 357
    Data columns (total 2 columns):
    date     358  non-null values
    price    358  non-null values
    dtypes: float64(1), int64(1)
    
    In [23]: df.head()
    Out[23]: 
             date  price
    0  1349720105  12.08
    1  1349806505  12.35
    2  1349892905  12.15
    3  1349979305  12.19
    4  1350065705  12.15
    In [25]: df['date'] = pd.to_datetime(df['date'],unit='s')
    
    In [26]: df.head()
    Out[26]: 
                     date  price
    0 2012-10-08 18:15:05  12.08
    1 2012-10-09 18:15:05  12.35
    2 2012-10-10 18:15:05  12.15
    3 2012-10-11 18:15:05  12.19
    4 2012-10-12 18:15:05  12.15
    
    In [27]: df.dtypes
    Out[27]: 
    date     datetime64[ns]
    price           float64
    dtype: object