Python Classes and dynamic class members

[acatejr]

I have a text file that I am parsing. Each line is of the form:

max_time 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

The first item is the field name and the next twelve items are values
for each month in the year. There are multiple lines each for some
different variable. I am able to parse this data easily enough, but
what I'd like to do is have a class that stores all this infomormation
using dynamic member attributes/fields and the resulting list of
values. For example, if the class WeatherData was instantiated and I
parsed the line above as so:

field_name = "max_time;
values = [0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

how could I get weather data to store values in an attribute called
"max_time"? Ultimately, something like this would be possible:

WeatherData.max_time
[0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

Any help would be appreciated.

 

[James Stroud]

I have a text file that I am parsing. Each line is of the form:

max_time 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

The first item is the field name and the next twelve items are values
for each month in the year. There are multiple lines each for some
different variable. I am able to parse this data easily enough, but
what I'd like to do is have a class that stores all this infomormation
using dynamic member attributes/fields and the resulting list of
values. For example, if the class WeatherData was instantiated and I
parsed the line above as so:

field_name = "max_time;
values = [0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

how could I get weather data to store values in an attribute called
"max_time"? Ultimately, something like this would be possible:

WeatherData.max_time
[0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

Any help would be appreciated.

setattr(Weatherdata, "max_time", max_time)

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

 

[John Machin]

I have a text file that I am parsing. Each line is of the form:

max_time 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

The first item is the field name and the next twelve items are values
for each month in the year. There are multiple lines each for some
different variable. I am able to parse this data easily enough, but
what I'd like to do is have a class that stores all this infomormation
using dynamic member attributes/fields and the resulting list of
values. For example, if the class WeatherData was instantiated and I
parsed the line above as so:

field_name = "max_time;
values = [0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

how could I get weather data to store values in an attribute called
"max_time"? Ultimately, something like this would be possible:

WeatherData.max_time
[0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

errrmm, WeatherData is the class, not an instance of the class. See
below.

Any help would be appreciated.

class WeatherData(object):
pass

# then, for each instance:
wd = WeatherData()
# for each line:
# parse input to obtain field_name and values
setattr(wd, field_name, values)

HTH,
John

 

[acatejr]

I have a text file that I am parsing. Each line is of the form:

max_time 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

The first item is the field name and the next twelve items are values
for each month in the year. There are multiple lines each for some
different variable. I am able to parse this data easily enough, but
what I'd like to do is have a class that stores all this infomormation
using dynamic member attributes/fields and the resulting list of
values. For example, if the class WeatherData was instantiated and I
parsed the line above as so:

field_name = "max_time;
values = [0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

how could I get weather data to store values in an attribute called
"max_time"? Ultimately, something like this would be possible:

WeatherData.max_time
[0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

Any help would be appreciated.

setattr(Weatherdata, "max_time", max_time)

--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/

Thanks a lot!!

I did find that creating and calling the following method works too:

def setAt(self, field, data):
expression = "self." + field + " = data"
exec(expression)

I just don't know which one would be more efficient, but I like setattr
better.

 

[James Stroud]

I have a text file that I am parsing. Each line is of the form:

max_time 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12

The first item is the field name and the next twelve items are values
for each month in the year. There are multiple lines each for some
different variable. I am able to parse this data easily enough, but
what I'd like to do is have a class that stores all this infomormation
using dynamic member attributes/fields and the resulting list of
values. For example, if the class WeatherData was instantiated and I
parsed the line above as so:

field_name = "max_time;
values = [0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]

how could I get weather data to store values in an attribute called
"max_time"? Ultimately, something like this would be possible:



WeatherData.max_time
[0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09,0.10,0.11,0.12]


Any help would be appreciated.

setattr(Weatherdata, "max_time", max_time)

Thanks a lot!!

I did find that creating and calling the following method works too:

def setAt(self, field, data):
expression = "self." + field + " = data"
exec(expression)

I just don't know which one would be more efficient, but I like setattr
better.

You have good taste. You probably want to steer away from exec() if you
ever have the inclination. Python usually has an "approved", or
pythonic, way of solving problems you may want to address with exec().

James


--
James Stroud
UCLA-DOE Institute for Genomics and Proteomics
Box 951570
Los Angeles, CA 90095

http://www.jamesstroud.com/