What is the method for converting a JSON file into an array list?

Question

What is the method for converting a JSON file into an array list?

I am looking to convert my JSON file into an arraylist that can be utilized to showcase the information on a webpage.

Here is my HTML file snippet:

var xmlhttp = new XMLHttpRequest();
 xmlhttp.onreadystatechange = function() {
 if(this.readyState == 4 && this.status == 200) {
    console.log(JSON.parse(this.responseText))
}
};
 xmlhttp.open("GET", "PATIENT51.txt", true);
 xmlhttp.send();

This is how my JSON file looks like:

{
“resourceType”:”RiskAssessment”,
“Notes”: [
{“date”: “05/13/2019”, “note”: “my notes”},
{“date”: “02/22/2018”, “note”: “cool”}
]
}

I am struggling to access the 05/13/2019, I have attempted using

myObj.Notes[0].note;

Unfortunately, it returns as "undefined". My end goal is to create a table where each date will have an associated note.

javascript json

Answer 1

Answer №1

Avoid using balanced quotes or similar characters in JSON. “ and ” are not considered valid JSON characters; use standard quotes instead. '"'

JSON.parse('{ \
“resourceType”:”RiskAssessment”, \
“Notes”: [ \
{“date”: “05/13/2019”, “note”: “my notes”}, \
{“date”: “02/22/2018”, “note”: “cool”} \
] \
}');

In my experience, Chrome throws the expected error:

VM18:1 Uncaught SyntaxError: Unexpected token “ in JSON at position 2
at JSON.parse ()
at js:13

Stick to using standard quotes "

Upon inspecting the outputted Object in console.log, you'll notice that the element where you want to retrieve values from is named 'Notes' and not note. Thus, you need to access the variable of interest using myObj.Notes[0].note.

myObj = JSON.parse('{ \
"resourceType":"RiskAssessment", \
"Notes": [ \
{"date": "05/13/2019", "note": "my notes"}, \
{"date": "02/22/2018", "note": "cool"} \
] \
}');
console.log(myObj);
console.log(myObj.Notes[0].note);

If you need to replace curly/balanced quotes in your code snippet with a file, you can follow the solution provided in this answer:

var xmlhttp = new XMLHttpRequest();
 xmlhttp.onreadystatechange = function() {
 if(this.readyState == 4 && this.status == 200) {
    console.log(JSON.parse(this.responseText.replace(/[\u2018\u2019\u201C\u201D]/g, '"')));
}
};
 xmlhttp.open("GET", "PATIENT51.txt", true);
 xmlhttp.send();

However, it's recommended that whatever generates PATIENTS1.txt uses standard quotes instead of balanced quotes.

Answer 2

Avoid using balanced quotes or similar characters in JSON. “ and ” are not considered valid JSON characters; use standard quotes instead. '"'

JSON.parse('{ \
“resourceType”:”RiskAssessment”, \
“Notes”: [ \
{“date”: “05/13/2019”, “note”: “my notes”}, \
{“date”: “02/22/2018”, “note”: “cool”} \
] \
}');

In my experience, Chrome throws the expected error:

VM18:1 Uncaught SyntaxError: Unexpected token “ in JSON at position 2
at JSON.parse ()
at js:13

Stick to using standard quotes "

Upon inspecting the outputted Object in console.log, you'll notice that the element where you want to retrieve values from is named 'Notes' and not note. Thus, you need to access the variable of interest using myObj.Notes[0].note.

myObj = JSON.parse('{ \
"resourceType":"RiskAssessment", \
"Notes": [ \
{"date": "05/13/2019", "note": "my notes"}, \
{"date": "02/22/2018", "note": "cool"} \
] \
}');
console.log(myObj);
console.log(myObj.Notes[0].note);

If you need to replace curly/balanced quotes in your code snippet with a file, you can follow the solution provided in this answer:

var xmlhttp = new XMLHttpRequest();
 xmlhttp.onreadystatechange = function() {
 if(this.readyState == 4 && this.status == 200) {
    console.log(JSON.parse(this.responseText.replace(/[\u2018\u2019\u201C\u201D]/g, '"')));
}
};
 xmlhttp.open("GET", "PATIENT51.txt", true);
 xmlhttp.send();

However, it's recommended that whatever generates PATIENTS1.txt uses standard quotes instead of balanced quotes.

What is the method for converting a JSON file into an array list?

Answer №1

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