问题描述
我是python的新手，正在尝试创建一个打开csv文件的程序.用户应该输入条形码，然后程序会找到该产品和该产品的成本.但是我得到了一个错误，这是我的线程的标题.这是我的代码.
I am new to python, and trying to create a program which opens a csv file. The user is supposed to enter a barcode , then the program finds that product and the cost of the product. However I got an error which is the title of my thread. Here is my code.
import csv # imports should go at the top of the file
def read_csv_file():
""" reads csv data and appends each row to list """
csv_data = []
with open("task2.csv") as csvfile:
spamreader = csv.reader(csvfile, delimiter=",", quotechar="|")
for row in spamreader:
csv_data.append(row)
return csv_data
def get_user_input():
""" get input from user """
while True:
try:
GTIN = int(input("input your gtin-8 number: "))
break
except:
print ("Oops! That was not a valid number. Try again")
def search_user_input():
""" search csv data for string """
search_user_input
gtin = get_user_input()
for row in PRODUCT_DATA:
#print(row) #debug print
if row[0] == str(gtin):
product = row[1]
price = round(float(row[2]),2)
print(product, price)
return(product, price)
repeat = input("not in there? search again? If so (y), else press enter to continue")
if repeat == 'y':
search_user_input() # calls function again in order to create a loop
def quantity():
gtin = 0
product = 0
price = 0.0
product_data = read_csv_file()
product,price = search_user_input()
product, price = search_user_input(str(gtin), product_price)
order = int(input("How much of " + product + " do you want?"))
price = round(price * order, 2)
print(quantity,price)
def order_making():
print("Apples")
PRODUCT_DATA = read_csv_file() # call function to read csv
quantity() # call the main function
推荐答案
我已经清理了search_user_input和quantity的流程.在某些情况下，您使用多个参数调用了search_user_input(它不接受它们)，并且使它递归.我在下面的代码中添加了一些注释.实际上，该函数在您的设置中返回了None，这会导致TypeError: 'NoneType' object is not iterable错误.
I have cleaned the flow up a bit for search_user_input and quantity. In some cases you were calling search_user_input with multiple arguments (it doesn't accept them) and you made it recursive. I have added some comments in the code below. In fact, that function was returning None in your setup, which leads to the TypeError: 'NoneType' object is not iterable error.
if __name__ == '__main__:'在您的代码中不是必需的，我已将其更多地包含在其中，以备日后在您要开始导入自己的模块时使用.有关此主题的更多信息，请参见此.
The if __name__ == '__main__:' is not necessary in your code, I've included it more as a heads-up for later on when you'll want to start importing your own modules. See this for more info on this topic.
import csv
def read_csv_file():
""" reads csv data and appends each row to list """
csv_data = []
with open("task2.csv") as csvfile:
spamreader = csv.reader(csvfile, delimiter=",", quotechar="|")
for row in spamreader:
csv_data.append(row)
return csv_data
def get_user_input():
""" get input from user """
while True:
try:
GTIN = int(input("input your gtin-8 number: "))
return GTIN # Breaks the loop and returns the value
except:
print ("Oops! That was not a valid number. Try again")
def search_user_input(product_data): # Pass the csv data as an argument
""" search csv data for string """
keep_searching = True
while keep_searching:
gtin = get_user_input()
for row in product_data:
if row[0] == str(gtin):
product = row[1]
price = round(float(row[2]),2)
return(product, price)
repeat = input("not in there? search again? If so (y), else press enter to continue")
if repeat != 'y':
keep_searching = False
return None # This is done implicitly, I'm just making it obvious
def quantity():
product_data = read_csv_file()
matches = search_user_input(product_data)
if matches: # Will not be True if search_user_input returned None
product, price = matches[0], matches[1]
order = int(input("How much of {} do you want?".format(product)))
price = round(price * order, 2)
print("That costs {}".format(price))
if __name__ == '__main__': # You'll need this in future for importing modules
# There was no need to read the csv_data here and make it global
quantity() # call the main function
这篇关于TypeError:"noneType"对象在csv中的Python中不可迭代的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！