在Python中将列表写入csv文件

Question

我目前正在使用pythonv2.10。我无法将数据写入csv文件。想知道是否有人能告诉我我做错了什么。我得到以下错误："TypeError: list indices must be integers, not tuple"-不确定如何更正此错误。另外，我想写一个csv文件，数据必须是字符串格式？你知道吗

理想情况下，我希望每一行都像： 名称，X1，Y1，X2，Y2，X3，Y3

以下是我的代码：

import csv

def main():
    my_coords = open('Geo_Coords.csv', 'a')
    coords = csv.reader(my_coords)

    how_many = raw_input("How many Geometries do you wish to enter? ")
    counter = 0
    coords = []

    while counter < how_many:
        geometry = raw_input("Geometry Name  ")
        first_coordE = raw_input("1st Co-ord (Easting) ")
        first_coordN = raw_input("1st Co-ord (Northing) ")
        sec_coordE = raw_input("2nd Co-ord (Easting) ")
        sec_coordN = raw_input("2nd Co-ord (Northing) ")
        third_coordE = raw_input("3rd Co-ord (Easting) ")
        third_coordN = raw_input("3rd Co-ord (Northing) ")
        counter = counter + 1

        my_coords.write(coords[[geometry],[first_coordE,first_coordN], [sec_coordE,sec_coordN], [third_coordE,third_coordN]] )

    my_coords.close()
    print my_coords

main()

Answer 1

import csv

def main():
    my_coords = open('Geo_Coords.csv', 'a')
    coords = csv.reader(my_coords)

好的，coords是csv.reader()对象的名称

    how_many = raw_input("How many Geometries do you wish to enter? ")

how many是字符串的名称，比如说"15"

    counter = 0
    coords = []

在这里你做了一件奇怪的事情，coords现在是一个空列表的名称，csv.reader()不再有引用它的名称。。。你知道吗

    while counter < how_many:

而且上面的说法很奇怪。。。你在比较int和string！在python2中，逻辑表达式string < integer总是True！你知道吗

        geometry = raw_input("Geometry Name  ")
        first_coordE = raw_input("1st Co-ord (Easting) ")
        first_coordN = raw_input("1st Co-ord (Northing) ")
        sec_coordE = raw_input("2nd Co-ord (Easting) ")
        sec_coordN = raw_input("2nd Co-ord (Northing) ")
        third_coordE = raw_input("3rd Co-ord (Easting) ")
        third_coordN = raw_input("3rd Co-ord (Northing) ")
        counter = counter + 1

到目前为止，还不错-但是请注意，您没有修改coords的值，因此当您使用名称coords时，您只是引用了一个空列表

        my_coords.write(coords[[geometry],[first_coordE,first_coordN], [sec_coordE,sec_coordN], [third_coordE,third_coordN]] )

在这里，您通过寻址引用空列表的内容；此外，寻址的语法是错误的，它必须是整数或切片对象—此外，.write(...)方法需要一个字符串，而您正在尝试一次编写一个字符串列表。。。你知道吗

    my_coords.close()
    print my_coords

这会打印出

<closed file 'Geo_Coords.csv', mode 'a' at 0x7efc8946a540>

---

The answerbyKoffee对我来说似乎完全足够了，所以我建议你接受它，并可能对它投赞成票。你知道吗

Answer 2

您的代码包含一些问题，您将coords重新分配为一个列表，在此之前它是一个csv对象，您使用的是csv.reader而不是csv.writer，我鼓励您阅读那里的文档：https://docs.python.org/2/library/csv.html

也许这能帮到你，我保留你用的结构，我只是修改了一点。你知道吗

import csv

def main():
    with open('Geo_Coords.csv', 'a') as my_coords:
        coords = csv.writer(my_coords)

        how_many = int(raw_input("How many Geometries do you wish to enter? "))
        # TODO: Check user input
        rows = []

        for _ in range(how_many):
            geometry = raw_input("Geometry Name  ")
            first_coordE = raw_input("1st Co-ord (Easting) ")
            first_coordN = raw_input("1st Co-ord (Northing) ")
            sec_coordE = raw_input("2nd Co-ord (Easting) ")
            sec_coordN = raw_input("2nd Co-ord (Northing) ")
            third_coordE = raw_input("3rd Co-ord (Easting) ")
            third_coordN = raw_input("3rd Co-ord (Northing) ")

            rows.append([geometry, first_coordE,
                         first_coordN, sec_coordE,
                         sec_coordN, third_coordE,
                         third_coordN])

        coords.writerows(rows)


if __name__ == "__main__":
    main()