python - 如何将列乘以csv中的常量

Question

我正在尝试将列中的值乘以 1.5

import csv

ids=[2,4,1,10,6,7,15,9]
names=["Joe","Steve","Samantha","Leah","Riley","Ashley","Sheyanne"]
salaries=[95000,35000.150000,99000,53215,23424,225000]

with open("q2.csv","w+",newline='') as file:
    filewriter=csv.writer(file)
    content=[ids,names,salaries]
    zipped=zip(*content)

    fieldnames=["id","name","salary"]

    filewriter.writerow(fieldnames)
    filewriter.writerows(zipped)

with open("q2.csv","r")as fileread:
    reader=csv.reader(fileread)
    next(reader,None)

    listJ=[]
    for row in reader:
        if len(row[1])<=3 or row[1].startswith("S"):
            listJ.append(row)

    for row in listJ:
        row[2]=row[2]*1.5
    print(listJ)

它会产生这样的结果。

[['2', 'Joe', '9500095000'], ['4', 'Steve', '35000.1535000.15'], ['1', 'Samantha', '9900099000']]

我试着用

for id,name,salary in listJ:
    salary=salary*1.5

这个给我

>TypeError: can't multiply sequence by non-int of type 'float'

我什至尝试使用 numpy.asarray 使工资列表浮动，但仍然不起作用。

谢谢

标签： pythoncsv

Answer 1

工资字段以字符串形式读入，因此您需要先将其转换为数字类型：

salary = float(salary) * 1.5

或者：

row[2] = float(row[2]) * 1.5