I have el next dataframe

from pandas import *
from numpy import *


data=read_csv('enero.csv')
data



           Fecha           DirViento  MagViento  
0   2011/07/01  00:00        318        6.6      
1   2011/07/01  00:15        342        5.5        
2   2011/07/01  00:30        329        6.6        
3   2011/07/01  00:45        279        7.5        
4   2011/07/01  01:00        318        6.0        
5   2011/07/01  01:15        329        7.1        
6   2011/07/01  01:30        300        4.7        
7   2011/07/01  01:45        291        3.1   

How to split the column Fecha in two columns,for example, get a dataframe as follows:

       Fecha     Hora     DirViento  MagViento  
0   2011/07/01  00:00        318        6.6      
1   2011/07/01  00:15        342        5.5        
2   2011/07/01  00:30        329        6.6        
3   2011/07/01  00:45        279        7.5        
4   2011/07/01  01:00        318        6.0        
5   2011/07/01  01:15        329        7.1        
6   2011/07/01  01:30        300        4.7        
7   2011/07/01  01:45        291        3.1 

You first have to be able to access each individual row and know what format the row is in; string, list, etc. We do not know this so any code would be shooting in the dark.

If the csv file contains the time data, then you might be better off to split date and time in the csv file.

Example on how to modify a CSV file ...

# data string from typical csv file
# header removed
csv_data = '''\
2011/07/01  00:00,318,6.6
2011/07/01  00:15,342,5.5
2011/07/01  00:30,329,6.6 
2011/07/01  00:45,279,7.5'''

mylist = csv_data.split('\n')
#print(mylist)  # test

newlist = []
for line in mylist:
    line_list = line.split(',')
    #print(line_list)  # test
    #print(line_list[0])  # test
    #print(line_list[0].split())  # test
    date, time = line_list[0].split()
    newlist.append([date, time, line_list[1], line_list[2]])

#print(newlist)  # test
csv_data_new = ""
for item in newlist:
    #print(','.join(item))  # test
    csv_data_new += ','.join(item) + '\n'

print(csv_data)
print('-'*30)
print(csv_data_new)

# optionally add header string
header = "Fecha,Hora,DirViento,MagViento\n"
csv_data_new = header + csv_data_new

fname = "new_data.csv"
with open(fname, "w") as fout:
    fout.write(csv_data_new)

''' result ...
2011/07/01  00:00,318,6.6
2011/07/01  00:15,342,5.5
2011/07/01  00:30,329,6.6 
2011/07/01  00:45,279,7.5
------------------------------
2011/07/01,00:00,318,6.6
2011/07/01,00:15,342,5.5
2011/07/01,00:30,329,6.6 
2011/07/01,00:45,279,7.5
'''

Now you can read the modified CSV file into pandas ...

''' pandas_read_csv101.py

file new_data.csv content ...
Fecha,Hora,DirViento,MagViento
2011/07/01,00:00,318,6.6
2011/07/01,00:15,342,5.5
2011/07/01,00:30,329,6.6 
2011/07/01,00:45,279,7.5

used Windows installer 
pandas-0.12.0.win32-py3.3.exe
'''

import pandas as pd

data = pd.read_csv('new_data.csv')

print(data)

''' result ...
        Fecha   Hora  DirViento  MagViento
0  2011/07/01  00:00        318        6.6
1  2011/07/01  00:15        342        5.5
2  2011/07/01  00:30        329        6.6
3  2011/07/01  00:45        279        7.5
'''
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