# [Tutor] Updating index of a list

Anshu Kumar anshu.kumar726 at gmail.com
Fri Oct 9 03:59:44 CEST 2015

```Hi Andrea,

You can use lambda or list comprehension to solve your problem in one step.

I am more comfortable with lambda so will explain that way.

andreea_list = [['1', ' james', ' 1', ' 90'], ['2', ' alice', ' 1', '
95'], ['5', ' jorgen', ' 1', '99']]
andrea_float_list = map(lambda x:float(x[0]),andreea_list)
print andrea_float_list

map is function which takes two arguments first is an anonymous function
called lamda which operates on each of the list element one at a time and
the other is list it self. you can read about lambdas here
http://www.python-course.eu/lambda.php

Thanks ,
Anshu

On Fri, Oct 9, 2015 at 1:10 AM, Andrea Nguy <andrea.nguy at gmail.com> wrote:

> Hi there,
>
> I’m trying to learn some Python programming on my own. What’s happening is
> that I am trying to take a list of a list as such: [['1', ' james', ' 1', '
> 90'], ['2', ' alice', ' 1', ' 95'], ['5', ' jorgen', ' 1', ' 99’]] (it
> continues) from a text file.
>
> However, what I am trying to do take the indexes of thelist[0][1] and
> theist[0][3] and times them by a float number - returning the list with all
> of the values multiplied according to the float.
>
> Is this possible? I am trying to iterate that throughout the entire list
> or would it be easier if I tried to change the list of the list into a
> dictionary for efficiency?
>
> Thanks!
>
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> To unsubscribe or change subscription options:
> https://mail.python.org/mailman/listinfo/tutor
>
```