numerical calculations with the items in a list

I am back again with another python query. I have been trying to do some calculations with the items present in a list. Here is the code:

import math

def Usage() :
    print "Usage :python beznew.py transcriptionsFile"

if __name__ == "__main__" :

    if len(sys.argv) != 2 : 
        Usage() 

    else :
        transcriptionFile = sys.argv[1]
        tFile = open(transcriptionFile, "r")

        for line in iter(tFile) :
            list = line.split()

            # changing the unit of time from 100 nano seconds to seconds
            list[0] = list[0] / 100000000
            list[1] = list[1] / 100000000

            # duration of each phoneme
            list = list[1] - list[0]

            # extracting the start time of each phoneme
            newlist = list.pop[0]    

            print list
            print newlist开发者_如何学运维

        close.tFile 

The input file looks like the following:

000000 1200000 pau

1200000 1600000 dh

1600000 2000000 ih

2000000 3100000 k

3100000 3400000 aa

3400000 3800000 r

I am trying to change the numerical values to seconds. And also trying to get the difference between first and second numbers. It would not allow me to divide. I dont understand what am I doing wrong. Thank you.

---

First, don't use list as a variable name. Every time you do that, a kitten dies.

Second, you should convert the strings you've extracted from your file to a number, preferably a Decimal if you value the precision. Currently you're trying to divide a string.

Third, nanoseconds are billionths of a second, not millionths.

Fourth, it's tFile.close(), not close.tfile.

Fifth, use for line in tfile:. A file descriptor is already an iterator.

Sixth, use with open(transcriptionfile, "r") as tfile: and be done with having to close it.

---

you can simplify your code as follows:

transcriptionFile = 'calculus.txt'

with open(transcriptionFile, "r") as tFile:
        for line in tFile :
                li = line.split()
                if li: 
                        new = ((int(li[1]) - int(li[0]))/10000000. , li[2])     
                        print li,'  ',new

The condition if li: is here to eliminate possible void lines.

Important points:

• don't call a list with the name list because list is the name of built-in function of Python

• in Python, 10/100 produces 0 ; you must put a dot to obtain the right result: 10./100 or 10/100.

• do the calculus list = list[1] - list[0] before dividing by 10000000, it is more precise

• with open(....) as handle: is better to open the files

Personally, I would do

transcriptionFile = 'calculus.txt'

with open(transcriptionFile, "r") as tFile:
        gen = (line.split() for line in tFile if line.strip())
        li = [((int(t2)-int(t1))/10000000.,phon) for (t1,t2,phon) in gen]
        print '\n'.join(map(str,li))

Note that I used 10000000. to divide: if 1600000 - 1200000 = 400000 is in a unit which is 100 nanoseconds, then 400000 / 10000000 is 0.04 second

Edit 1

transcriptionFile = 'calculus.txt'

with open(transcriptionFile, "r") as tFile:
        gen = (line.split() for line in tFile if line.strip())
        firstVals, lapTimes = [],[]
        for (t1,t2,phon) in gen:
                firstVals.append( (int(t1)/10000000.,phon) )
                lapTimes.append( (int(t2)-int(t1))/10000000.,phon) )

---

line.split() returns a list of strings. Try list[0] = float(list[0]) / 100000000.

This converts each string to a number which supports division before you do your calculations.

---

You do not convert the strings to numerical values. In order to conduct mathematical operations on your data, you have to convert the either to int or float objects:

valueA = int(list[0]) / 100000000
valueB = int(list[1]) / 100000000