分割文件中的列表

Question

So I have a text file with multiple lines Each line has the name, grade, and birthyear or a student, seperated by semi colons

How do I make a function so that it sums all of the second items in each line, and then averages them?

for example,

mary; 0; 1995
jay; 50; 1995

classAverage = 25

Really confused with this.

Here is my code so far, it doesn't give me errors, but when I print it says <function classAverage at 0x0000000004C1ADD8>

from kiva.constants import LINES

def process(name):
    f = open(name)
    answer = []
    for line in f:
        answer.append(line.strip())
    return answer
def classAverage(data):
    data = process(filename)
    data.split()
    adding = []
    for line in data:
        adding = adding + data[1]
    return adding/(line)


if __name__ == '__main__':
    filename = "grades.txt"
    data = process(filename)
    for each in data:
        print each
    print classAverage(data)
    #print "Average grade is ", classAverage(data)
    year1 = 1995
    year2 = 1997
    print "Number born from ",year1,"to",year2,"is",
    #print howManyInRange(data, year1, year2)

Answer 1

def ave(x):
    return sum(x) / len(x)
with open(name, newline='') as csvfile:
    print(ave([float(row[1]) for row in csv.reader(csvfile, dilimeter=';')]))

Answer 2

I get an error when I run that code, but you would get that output if you had "print classAverage" instead of "print classAverage(data)", so maybe you copied a slightly different version than what produced that output.

You have several problems in your code. The first is that data is a list and you are trying to call data.split(). You also never split the text by ";" and your average formula is off. I made some slight adjustments to get it to do what I think you intend:

def process(name):
f = open(name)
answer = []
for line in f:
    answer.append(line.strip().split(';'))
return answer


def classAverage(data):
    adding = 0.0
    for line in data:
        adding = adding + float(line[1])
    return adding / len(data)


if __name__ == '__main__':
    filename = "grades.txt"
    data = process(filename)
    for each in data:
        print each
    print classAverage(data)
    # print "Average grade is ", classAverage(data)
    year1 = 1995
    year2 = 1997
    print "Number born from ", year1, "to", year2, "is",
    # print howManyInRange(data, year1, year2)

That said, pandas is really good at parsing data files and then calculating metrics on the data. Parsing the file is a single line using pandas. Here is the equivalent code using pandas:

import pandas as pd


if __name__ == '__main__':
    df = pd.read_table('grades.txt', sep=';', names=['name', 'score', 'year'])
    print 'Average score = ', df.score.mean()
    year1 = 1995
    year2 = 1997
    print "Number born from ", year1, "to", year2, "is", df[(df.year >= year1) & (df.year <= year2)].name.count()

Output:

Average score =  25.0
Number born from  1995 to 1997 is 2

Answer 3

you should modify function classAverage like this:

def classAverage(data):
    # you do not need to re-process the file, just use the data
    adding = []
    for line in data:
        line = line.split(';')
        adding.append(float(line[1].strip()))
    return sum(adding) / len(adding)