CODEWITHSUNDEEP
stringlistprologswi-prolog
J.FF
J.FF

Reputation: 41

Keep String property after inseriting to a list

I´m doing a project where I need to recognize specific strings and add them to a list. Im using this method to insert them in a specific position:

insertAt(E,N,Xs,Ys) :-
   same_length([E|Xs],Ys),
   append(Before,Xs0,Xs),
   length(Before,N),
   append(Before,[E|Xs0],Ys)

The problem is that when I insert any String for example '4X',in my list appears 4X, as a number and a variable. How can i keep the single quotes after the insert? This is the line that gives me problems:

insertAt('>500',0,ListA,ListB),writeln(ListB).

When the list show in promt it looks like [>500],without the quotes.

Upvotes: 1

Views: 30

Answers (1)

Guy Coder
Guy Coder

Reputation: 24976

Simple example since you didn't indicate how you are creating 4X

test :-
    append(["4x"],[],New),
    write(New).

Example run:

?- test.
[4x]
true.

After updates in comments.

Is there a way to write while maintaining the quotes?

?- print('4x').
'4x'
true.

?- print([a,b,'4X',d]).
[a,b,'4X',d]
true.

Of note: portray/1

I have never used portray/1 but you might.

Upvotes: 1

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