Question

I’d like to:

• Check a key / value at position i
• Check to see if key / value contains a string
• delete / store in another variable either the key / value

The equivelant of this Java code:

//Some list...
ArrayList<String> example;
...
//Index into data structure
example.get(i);
//Check for some string...
if (example.get(i).contains("someText")){

    somestuff;

}
//Store in some other variable
exam = example.get(i)

That’s what I’m effectively trying to in Java, however I’d like to be able to do that with Python dictionarties however I’m not sure if this is possible, as I find the Python documentation rather hard to read.

Answer 1

Python dictionaries are implemented as hash tables, so there is no intrinsic ordering; therefore, “position i” is a totally nonsensical concept for a dict — it’s like asking for the dict entry that’s most yellow, or that least resembles a llama… those concepts just don’t apply to dict entries, and “position i” is just as totally inapplicable.

Where does that i come from, i.e., what’s the real issue you’re trying to solve? If your requirement is to iterate over the dictionary, you do that directly, without the crutch of a “numeric index”. Or, if you do need to keep some specific order or other, then you don’t use a dict, but rather some different data structure. If you explain exactly the purpose you’re trying to address, I’m sure we can help you.