分割文件中的列表

Question

所以我有一個包含多行的文本文件，每行都有名稱，年級和出生年月或一個學生，以半冒號分隔

如何制作一個函數，使其對每一行中的所有第二個項目求和，然后取平均值？

例如，

mary; 0; 1995
jay; 50; 1995

classAverage = 25

真的很困惑。

到目前為止，這是我的代碼，它沒有給我錯誤，但是當我打印時，它說<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

運行該代碼時出現錯誤，但是如果使用“ print classAverage”而不是“ print classAverage（data）”，則會得到該輸出，因此也許您復制的版本與產生該輸出的版本略有不同。

您的代碼中有幾個問題。 首先是data是一個列表，您正在嘗試調用data.split（）。 您也永遠不會用“;”分隔文本 並且您的平均公式已關閉。 我做了一些細微的調整，以使其能夠執行我認為您打算的操作：

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)

也就是說，pandas非常擅長解析數據文件，然后計算數據指標。 使用pandas解析文件僅需一行。 這是使用pandas的等效代碼：

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()

輸出：

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

Answer 3

您應該像這樣修改函數classAverage：

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)