Question

我是Python新手。我正在尝试在CSV文件中写入数字。第一个数字构成行的第一个元素。第二个数字，然后一个新行应该开始。但是，我的代码的工作方式，而不是将第二个元素添加到同一行，它创建一个新行。

例如我想要的是：

a1,b1
a2,b2

但我得到的是：

a1
b1
a2
b2

我使用循环连续将值写入CSV文件：

n = Ratio # calculated in each loop
with open('ex1.csv', 'ab') as f:
    writer = csv.writer(f)
    writer.writerow([n])
    ...

m = Ratio2 # calculated in each loop
with open('ex1.csv', 'ab') as f:
    writer = csv.writer(f)
    writer.writerow([m])

我希望结果的格式为

n1,m1
n2,m2

Answer 1

写入文件然后将其读回并打印的示例：

import csv

with open('ex1.csv', 'w') as f: # open file BEFORE you loop
    writer = csv.writer(f)      # declare your writer on the file

    for rows in range(0,4):     # do one loop per row
        myRow = []              # remember all column values, clear list here
        for colVal in range(0,10):   # compute 10 columns
            m = colVal * rows        # heavy computing  (your m or n)
            myRow.append(m)          # store column in row-list

        writer.writerow(myRow)  # write list containing all columns 

with open('ex1.csv', 'r') as r:  #read it back in 
    print(r.readlines())         # and print it

输出：

['0,0,0,0,0,0,0,0,0,0\r\n', '0,1,2,3,4,5,6,7,8,9\r\n', '0,2,4,6,8,10,12,14,16,18\r\n', '0,3,6,9,12,15,18,21,24,27\r\n']

转换为

文件

0,0,0,0,0,0,0,0,0,0
0,1,2,3,4,5,6,7,8,9
0,2,4,6,8,10,12,14,16,18
0,3,6,9,12,15,18,21,24,27

您还可以将每个行列表（通过myList[:]复制）填充到另一个列表中，并使用writer.writerows([ [1,2,3,4],[4,5,6,7] ])一次性写入所有行。

请参阅：https://docs.python.org/2/library/csv.html#writer-objects或https://docs.python.org/3/library/csv.html#writer-objects

CSV编写器转到每个输入值的下一行

1 个答案: