从元组列表中查找与用户输入对应的值

Question

As a foreword, I'm quite new to python, and coding in general.

I'm trying to get the following code to find the specific values in the foodgroups tuple that match with user input (ie: Dairy, Nuts, and Grain) and attach them to Output (ie: Dairy and Nuts). The line with Output was gotten from another website when I was first making this. The code works when the user provides an input that only contains one item without any symbols or spaces (ie: Dairy) but anything extra causes Output to be blank when printed.

userinput = input("Enter foodgroups ate in the last 24hrs : ").title()
foodgroups = ("Dairy","Nuts","Seafood","Chocolate")

Output = list(filter(lambda x:userinput in x, foodgroups))

if foodgroups[0] or foodgroups[1] or foodgroups[2] or foodgroups[3] in userinput:
  print(Output,"is present in your list, " + userinput)
else:
  print("Negative.")

I've thought of swapping around foodgroups and userinput , but that results in a TypeError, and turning the tuple into a string has Output always return blank.

I've asked others how to fix this, but they've had no better luck. Any help is appreciated!

Answer 1

If userinput is a comma separated string then split it and use a list:

userinput = input("Enter foodgroups ate in the last 24hrs : ")
foodgroups = ("Dairy","Nuts","Seafood","Chocolate")
uin = userinput.split(",")
grp = []
for x in uin:
  if x in foodgroups:
    grp.append(x)

grp is the user defined foods in foodsgroup

Answer 2

The main thing is that you want to use split to separate individual words from the user input into a list of words. I also swapped x and seafoods in your lambda.

If the user separates each word by one or more spaces, here's how to change your code to work:

userinput = input("Enter foodgroups ate in the last 24hrs : ").title()
foodgroups = ("Dairy","Nuts","Seafood","Chocolate")

userfoods = userinput.split()

Output = list(filter(lambda x: x in userfoods, foodgroups))

print(Output,"is present in your list, " + str(userinput))

Answer 3

As other's mention, you need to use split() to separate individual items in the input:

userfoods = userinput.split()

But even after that your if condition isn't correct:

if foodgroups[0] or foodgroups[1] or foodgroups[2] or foodgroups[3] in userinput:

The thing to realize here is that or and in are operators that only work with the immediately adjacent 2 values. We can add parentheses to see how this works:

if (((foodgroups[0] or foodgroups[1]) or foodgroups[2]) or (foodgroups[3] in userinput)):

This means that foodgroups[0] or foodgroups[1] evaluates to just the value of foodgroups[0] , so foodgroups[1] is basically ignored. This isn't what you want. Instead, you need to check in for each item:

if foodgroups[0] in userinput or foodgroups[1] in userinput or foodgroups[2] in userinput or foodgroups[3] in userinput:

But as you can see this gets very lengthy. So using a loop or list comprehension or generator expression can reduce the amount of code you need to write as others have already shown.