using another dictionary in each iteration-CodePudding

okay so I want my for loop to change the variable if there is an KeyError,

numlist1 = {"one": 1}

numlist2 = {"two": 3}

numlist3 = {"three": 3}

userinputfix = ["two", "five"]

newlist = []
for x in userinputfix:
    newlist.append(numlist1[x])

So if there is no "two" in numlist1, it should repeat the loop replacing numlist1 with numlist2, numlist3,...

I tried to use handling exceptions methdod.

numlist1 = {"one": 1}

numlist2 = {"two": 3}

numlist3 = {"three": 3}

userinputfix = ["two", "five"]

y = 1
newlist = []
for x in userinputfix:
    try:
        newlist.append(numlist{y}[x])
    except KeyError:
        y  = 1

something like this but my code is not correct.

CodePudding user response：

So, I 'think' you want to produce an output of [2] for the above? I.e. taking a list of matching values from each of the lists ignoring those that don't have a matching key?

You can't access 'numlist2' by using 'numlist{2}' as you're attempting there. If there is a short, fixed number of lists, you need to iterate them specifically:

newlist = []
for x in userinputfix:
    for d in (numlist1, numlist2, numlist3):
        try:
            newlist.append(d[x])
        except KeyError:
            pass

If you want to use any dictionary that starts "numbest", then it'll be something horrible like...

dicts = [globals()[x] for x in globals() if x.startswith("numlist") and type(globals()[x]) == dict]
newlist = []
for x in userinputfix:
    for d in dicts:
        try:
            newlist.append(d[x])
        except KeyError:
            pass

This makes a list of all global variables that start 'newlist' and are dictionaries, then those are iterated.

CodePudding user response：

Here is using dict.get and while loop with try except and eval

numlist1 = {"one": 1}
numlist2 = {"two": 3}
numlist3 = {"three": 3}
numlist4 = {"four": 4}

userinputfix = ["four", "two", "five", "one"]

newlist = []
i = 1
for x in userinputfix:
    while True:
        try:
            val = eval(f'numlist{i}').get(x)
            if val != None:
                newlist.append(val)
            i  = 1
        except NameError:
            break
    i = 1

print(newlist)

# [4, 3, 1]

For each x in userinputfix, it will try to find x in every dictionaries variable by increasing i by 1 until it found NameError and resetting i back to 1 to continue to the next x. If the value is None or x not found, it'll not get appended to newlist.