Panda: read csv datetime

Cara 1

import pandas
x = pandas.read_csv('/home/onno/TensorFlow/TEMP-train.csv', parse_dates=True, index_col='DateTime', 
                                names=['DateTime', 'X'], header=None, sep=',')
x

Cara 2

import numpy as np
import matplotlib.pyplot as plt
import pandas as pd

infile = '/home/onno/TensorFlow/TEMP-train.csv'
mydateparser = lambda x: pd.datetime.strptime(x, "%Y-%m-%d %H:%M:%S")
df = pd.read_csv(infile, sep=',', names=['datetime', 'value'], parse_dates=['datetime'], date_parser=mydateparser)