Name is not defined when using eval() in Python-CodePudding

I am currently doing miniscript that is sending documents to a specific path based on a code I enter.

The code is basic, but I get an error which I really don't understand.

When I run the following code:

en = "English"
source = eval(input("Source language?\n"))
print (source)

If I hit 'en' I get English without any errors.

But if I run the same without input:

en = "English"
eval(en)

I get "name 'English' is not defined"

Basically, I want to use some of eval() functions in my code without the input() function. Where I am wrong?

CodePudding user response：

eval expects a string as its argument. By passing it en, you're giving it the string "english". Instead, you probably want

eval("en")

However, using eval is generally bad practice. I'd look into alternative ways of doing what you're after.

CodePudding user response：

Usually there is never any need to use eval in Python:

languages = {'fr': 'french', 'gr': 'greek', 'en': 'english'}
source = languages.get(input("Source language?\n"), 'Undefined language!')
print(source)

Out:

Source language?
gr
greek