python - 搜索 CSV 文件 python

Question

我已经编写了一个程序来调用文件中的汇率，但它打印了到达行的输出，存在逻辑错误，但我找不到它。

import csv
exRtFile = open ('exchangeRate.csv')
exchReader = csv.reader(exRtFile)
newCurrency = raw_input("Please enter the currency you would like to convert to: ")
for row in exchReader:
        currency = row[0]
        if currency == newCurrency:
            newRt = row[1]
            print(newRt)
            break

print("Sorry, that is not a valid currency")

文件:

Pound Sterling,1
Euro,1.22
US Dollar,1.67
Japanese Yen,169.948

Answer 1

如果我正确理解您的问题，问题是它打印 "Sorry..." 行，即使它在文件中找到了货币。为防止这种情况，您可以 add an else to the for loop .

for row in exchReader:
    currency = row[0]
    if currency == newCurrency:
        newRt = row[1]
        print(newRt)
        break
else:
    print("Sorry, that is not a valid currency")

这样，else block 只会在循环正常退出时执行，即没有 break。