如何将所有循环输出放入变量中（用于生成输出文件）？ （CSV 相关）

Question

我对使用 python 很陌生，所以我希望你能在这里帮助我。我必须编写一个程序来打开一个 csv 文件，读取它并让你通过输入数字来选择你想要的列。这些必须放在一个新文件中。问题是：在输入我想要的列并将“X”启动主要部分之后，它会生成我想要的内容，但是通过使用循环，而不是打印包含它的变量。但是对于 csv-writer 我需要一个包含它的变量。有任何想法吗？在这里你有我的代码，有问题随时问。 csvfile 就像：

john, smith, 37, blue, michigan
tom, miller, 25, orange, new york
jack, o'neill, 40, green, Colorado Springs
...etc

代码是：

import csv

with open("test.csv","r") as t:
    t_read = csv.reader(t, delimiter=",")
    t_list = []
    max_row = 0
    for row in t_read:
        if len(row) != 0:
            if max_row < len(row):
                max_row = len(row)
            t_list = t_list + [row] 
            print([row], sep = "\n")
    twrite = csv.writer(t, delimiter = ",")
    tout = []
    counter = 0
    matrix = []
    for i in range(len(t_list)):
        matrix.append([])
    print(len(t_list), max_row, len(matrix), "Rows / Columns / Matrix Dimension")
eingabe = input("Enter column number you need or X to start generating output: ")
nr = int(eingabe)
while type(nr) == int:
    colNr = nr-1
    if max_row > colNr and colNr >= 0:
        nr = int(nr)
        # print (type(nr))
        for i in range(len(t_list)):            
            row_A=t_list[i]            
            matrix[i].append(row_A[int(colNr)])
            print(row_A[int(colNr)])
        counter = counter +1
        matrix.append([])
    else:
        print("ERROR")

    nr = input("Enter column number you need or X to start generating output: ")

    if nr == "x":
        print("\n"+"Generating Output... "  + "\n")        
        for row in matrix:
    # Loop over columns.           
            for column in row:     
                print(column + " ", end="")
            print(end="\n")

    else:
        nr = int(nr)

print("\n")


t.close()

Answer 1

嗯，您拥有 matrix 所需的一切，除了添加不需要的行的错误行：

    counter = counter +1
    matrix.append([])   # <= remove this line
else:
    print("ERROR")

然后你可以简单地做：

if nr == "x":
    print("\n"+"Generating Output... "  + "\n")        
    with open("testout.csv", "w") as out:
        wr = csv.writer(out, delimiter=",")
        wr.writerows(matrix)