On 2013-04-11 03:39, Cousin Stanley wrote:
for row in list_tuples :
print ' ' , row.date , row.time , row.col1 , row.col3 , row.col4
file_source.close()
Oh, that's great - thank you - I didn't know this named-tuple container
before... I'm still wondering whether or not it's the optimal container
type for me, because I just added a bit of matplotlib-code:
-----------------
#!/usr/bin/env python
import csv
from collections import namedtuple as NT
file_source = open( 'someone.csv' )
# -------------------> individual column names ---------------
nt = NT( 'csv_data' , 'date time col1 col2 col3 col4 col5 col6' )
list_tuples = [ ]
for this_row in csv.reader( file_source ) :
# unpack the current row
zed , one , two , tre , fur , fiv , six = this_row
# split the date and time
d , t = zed.split( 'T' )
# convert individual columns in row to a named tuple
this_tuple = nt( d ,
t ,
float( one ) ,
int( two ) ,
int( tre ) ,
float( fur ) ,
int( fiv ) ,
int( six ) )
# save the current named tuple into a list
list_tuples.append( this_tuple )
# update_data_base( this_tuple )
# .... or ....
# update_data_base( choose individual columns )
file_source.close()
# individual elements of the named tuples
# can be accessed by name
#
# this might be convenient for settup up
# data for plots of diffeent columns
x=[]
y=[]
print
for row in list_tuples :
print ' ' , row.date , row.time , row.col1 , row.col3 , row.col4
x.append(row.col3)
y.append(row.col4)
import matplotlib.pyplot as plt
plt.plot(x,y)
plt.ylabel('some numbers')
plt.show()
-----------------
As you can see, in order for me to make the x- and y-vectors, I need to
make a for-loop to access the individual rows in list_tuples and then I
append to the x- and y- lists...
Is there any clever way of avoiding this for loop, for either this
container or another clever container type?
If there isn't, then this is absolutely also an acceptable/good solution
for me... I also use Matlab and for matrices you can type e.g. plot(
matrix(:,3), matrix(:,4) ) to plot columns 3 against column 4. But
Matlab also has this problem, that it cannot store strings and numbers
in the same matrix - matrices must entirely be numeric, which my data
isn't (due to 1st column)...
Thanks for any input, if someone has any good ideas...
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