Question

I'm opening a lot of files at the beginning of my program and I'd like to avoid using 50+ separate lines of 'with open(....) as ....'. I'm looking for a way to map the file names to the variable names that the data will be stored in so that I can use a 'for' loop to open all files and save a lot of lines of code.

It seemed intuitive to me that a dictionary would suit this purpose well, but if I use the variable names as values, I get a 'name 'variableName' is not defined' error. I also tried storing the variable names as strings and while this doesn't produce an error message, it also doesn't seem to actually store the data (ie when I try to call the variable afterwards, it says the variable is not defined).

fileMapDict = {'file1': var1, 'file2': var2, 'file3': var3}

for file in fileMapDict:
    with open(file, 'r') as data:
        fileMapDict[file] = json.load(data)

As I say, this code produces a variable not defined error when I run the code, can anyone suggest a way to make this work?

Answer 1

You don't need to have a separate variable if you have the data in the dictionary.

files = ['file1', 'file2', 'file3']  # list of file names to open
fileMapDict = {}  # empty dictionary to store the data in

for file in files:  
    with open(file, 'r') as data:
        fileMapDict[file] = json.load(data)  # write data to dictionary with the file name as the key

Naming previously undefined variable names from a dictionary value?

1 个答案: