Python, making a float of a list

[MaxManus]

I have made a list of data from a file, the file contains numbers and I want to calculate with the numbers. How do I make a float of a list where a[1] is: ['0.00500006128645'], I tried to just use float, but then I got:
float() argument must be a string or a number

 

[Dick]

map(float,a) will give you a list of floats.

 

[MaxManus]

I'm sorry. English is not my native language. I have a list of the acceleration of an object at some discrete and equally spaced points. And I am supposed to calculate the velocity by computing the integral numerically, but I can't manage to get the floats oit of the list.

 

[Dick]

If you do a=map(float,a) then a is now a list of floats. The first float is a[0], etc.

 

[MaxManus]

I tried, but I just got: TypeError: float() argument must be a string or a number

f = open("acc.dat", "r")a = []
for lines in f:
numbers = lines.split()
a.append(numbers)

f.close()

a = map(float,a)

 

[Dick]

Add a 'print a' statement before the 'map' statement to see what is actually going into the 'map'. You'll see that it's not a list of strings. It's a LIST of 'lists of strings'. You don't really want to append the list of strings 'lines.split()' to a, you want to concatenate it. Change 'a.append(numbers)' to 'a=a+numbers'. Python is VERY easy to debug. Use print statements to follow the program flow. If you don't understand exactly what a function does, play with it using the interactive interpreter.

 

[MaxManus]

Thank you.