Question

我正在尝试编写一个带有代码和csv文件的货币转换器，其中可以编辑csv文件以节省使用之间的新汇率。但是我在写入文件并更改速率时遇到问题：

 def change():
    print()
    print()
    print()
    print("1) Change existing exchange rate.")
    print("2) Add new exchange rates.")
    print("3) Quit.")
    exRtFile = open ('exchangeRate.csv')
    exchReader = csv.reader(exRtFile)
    exchWriter = csv.writer(exRtFile)
    loop2=0
    while loop2==0:
        selected=int(input("Please select an option: "))
        if selected == 1:
            change = input("What rate would you like to change: ")
            changeRt = float(input("What would you like to change the rate to: "))
            for row in exchReader:
                currency = row[0]
                if currency == change:
                    crntRt = row[1]
                    crntRt = changeRt
                    exchWriter.writerows(crntRt)

继承人和输入/输出的例子：

1) Change existing exchange rate.
2) Add new exchange rates.
3) Quit.
Please select an option: 1
What rate would you like to change: Euro
What would you like to change the rate to: 1.23
Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    converter()
  File "py", line 21, in converter
    change()
  File "py", line 91, in change
    exchWriter.writerows(crntRt)
TypeError: writerows() argument must be iterable

Answer 1

writeRows()，就其本质而言，期望一个变量包含一堆值，每个值包含要写入输出文件中一行的数据。

因为您提供writerows()一个float值，所以它通过告诉您它不知道如何将其转换为多行来进行响应 - 在＆＃34 ; Python说＆＃34; must be iterable表示＆＃34;我无法计算如何从您给我的项目中获取多个值＆＃34;。

您的代码中可能还有许多其他问题。特别是：

 crntRt = row[1]
 crntRt = changeRt
 exchWriter.writerows(crntRt)

让我觉得你在某种程度上期望在你的输出中看到row[1]的值，但是你不会因为下一行用新的汇率覆盖该值。

写入CSV文件。 TypeError：writerows（）参数必须是可迭代的

1 个答案: