CODEWITHSUNDEEP
python
user1313198
user1313198

Reputation:

In python, detect type, then cast to that type

In support of some legacy code, I have to read a text file and parse it for statements like x=102 and file=foo.dat that might be used to overwrite default values. Note that the second one there is not file='foo.dat'; these aren't python statements, but they're close.

Now, I can get the type of the default object, so I know that x should be an int and file should be a str. So, I need a way to cast the right-hand side to that type. I'd like to do this programmatically, so that I can call a single, simple default-setting function. In particular, I'd prefer to not have to loop over all the built-in types. Is it possible?

Upvotes: 3

Views: 747

Answers (2)

Mike
Mike

Reputation: 20196

It's actually pretty easy:

textfromfile = '102'
defaultobject = 101
value = (type(defaultobject))(textfromfile)

Now, value is an int equal to 102.

Upvotes: 0

Amber
Amber

Reputation: 526583

# Get the type object from the default value
value_type = type(defaults[fieldname])

# Instantiate an object of that type, using the string from the input
new_value = value_type(override_value)

Upvotes: 5

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