I'm getting an error in this code:
void main() {
List<String> wave(String str) {
List<String> results = [];
String newStr;
int i = 0;
for (String ltr in str.split('')) {
newStr = str;
if (ltr != ' ') {
newStr[i] = ltr.toUpperCase();
results.add(newStr);
}
i++;
}
return results;
}
print(wave(' gap '));
}
the error is at the line:
newStr[i] = ltr.toUpperCase;
Despite when I try print(newStr[i]); I don't get an error and the code is executed correctly!
In Dart String operation, operator[] returns a string. Which means, array[index] is used for getting the string in the index position. That is why you're getting that error, because you can't set at specific index using this operator[] in dart. See the documentation for details.
To replace at the specific index in dart, you can use replaceFirst(Pattern from, String to, [int startIndex = 0]) as the other answer mentioned. Or, you can use substring(int start, [int? end]) as follows:
if (ltr != ' ' && i < newStr.length) {
newStr = newStr.substring(0, i) + ltr.toUpperCase() + newStr.substring(i+1);
results.add(newStr);
}
To make the code bug free, I've added the checking of the value of i in it. You should add the checking to avoid out of bound access.
try to replace
newStr[i] = ltr.toUpperCase();
to
newStr = newStr.replaceFirst(ltr,ltr.toUpperCase(),i);
So the result will be [ Gap , gAp , gaP ]
Honestly, I don't know how char is defined in Dart, but I think accessing index of String is kind of getter, thus cannot be set to a new value.
I'm trying to set up my first discord bot to be able to replace certain letters with other letters, but I am extremely new to coding in javascript.
function debunkCommand(arguments, recievedMessage) {
if (arguments.length > 0) {
function strReplace(){
var myStr = argument;
var newStr = myStr.replace(/l/gi, "w");
var newStr = myStr.replace(/r/gi, "w");
receivedMessage.channel.send(newStr)
}
} else {
receivedMessage.channel.send("that's impossible to debunk")
}
}
expected to be able to write "!debunk hello" and have the bot send back a message saying "hewwo"
function debunkCommand(args, receivedMessage) {
if (args.length) {
/*
arguments is an array of strings, doing 'arguments.join(" ")' will join these strings into one
/[lr]+/gi will match any instances of 'l' or 'r'
it's also a good idea to rename your "arguments" parameter to "args", since "arguments" is already a standart js object
*/
receivedMessage.channel.send(args.join(" ").replace(/[lr]+/gi, "w"));
} else {
receivedMessage.channel.send("that's impossible to debunk");
};
};
I am looking to extract certain values from a JSON path of arrays and objects and use these values for further processing and am struggling with accessing those elements. Here is the JSON response:
[
{
"od_pair":"7015400:8727100",
"buckets":[
{
"bucket":"C00",
"original":2,
"available":2
},
{
"bucket":"A01",
"original":76,
"available":0
},
{
"bucket":"B01",
"original":672,
"available":480
}
]
},
{
"od_pair":"7015400:8814001",
"buckets":[
{
"bucket":"C00",
"original":2,
"available":2
},
{
"bucket":"A01",
"original":40,
"available":40
},
{
"bucket":"B01",
"original":672,
"available":672
},
{
"bucket":"B03",
"original":632,
"available":632
},
{
"bucket":"B05",
"original":558,
"available":558
}
]
}
]
I tried accessing the root elements with $ but I could not get further with it.
Here is the test method that I have written. I want to extract the value for od_pair and within each od_pair, I need to be able to retrieve the bucket codes and their available numbers.
public static void updateBuckets(String ServiceName, String DateOfJourney) throws Exception {
File jsonExample = new File(System.getProperty("user.dir"), "\\LogAvResponse\\LogAvResponse.json");
JsonPath jsonPath = new JsonPath(jsonExample);
List<Object> LegList = jsonPath.getList("$");
// List<HashMap<String, String>> jsonObjectsInArray = jsonPath.getList("$");
int NoofLegs = LegList.size();
System.out.println("No of legs :" + NoofLegs);
for (int j = 0; j <= NoofLegs; j++)
// for (HashMap<String, String> jsonObject : jsonObjectsInArray) {
{
String OD_Pair = jsonPath.param("j", j).getString("[j].od_pair");
// String OD_Pair = jsonObject.get("od_pair");
System.out.println("OD Pair: " + OD_Pair);
List<Object> BucketsList = jsonPath.param("j", j).getList("[j].buckets");
int NoOfBuckets = BucketsList.size();
// System.out.println("OD Pair: " + OD_Pair);
System.out.println("no of Buckets: " + NoOfBuckets);
for (int i = 0; i < NoOfBuckets; i++) {
String BucketCode = jsonPath.param("j", j).param("i", i).getString("[j].buckets[i].bucket");
String Available = jsonPath.param("j", j).param("i", i).getString("[j].buckets[i].available");
int BucketCodeColumn = XLUtils.getBucketCodeColumn(BucketCode);
int ServiceRow = XLUtils.getServiceRow(ServiceName, DateOfJourney, OD_Pair);
System.out.println("Row of " + ServiceName + ":" + DateOfJourney + "is:" + ServiceRow);
System.out.println("Bucket Code column of " + BucketCode + " is: " + BucketCodeColumn);
XLUtils.updateAvailability(ServiceRow, BucketCodeColumn, Available);
}
}
}
}
This is the error I see:
Caused by:
org.codehaus.groovy.control.MultipleCompilationErrorsException: startup
failed:
Script1.groovy: 1: unexpected token: [ # line 1, column 27.
restAssuredJsonRootObject.[j].od_pair
Can someone help me please?
I would suggest parsing your JSON into Java classes to ease the processing.
How to do that?
First, we need to create Java classes which will represent the JSON you provided.
Let's analyze the JSON.
Starts with an array. The array contains multiple JSON Object. These objects contain od_pair value and array of objects called buckets.
Let's create a class (you can name it whatever you want) Pair
public class Pair {
public String od_pair; //this name is important because it corresponds with the json element's name!
public List<BucketObject> buckets; //same here!
}
This class represents a single JSON Object in the main Array. It contains od_pair value AND nested JSON Array but in Java representation -> List of BucketObject classes. Let's create BucketObject class:
public class BucketObject { //this name is NOT importnat
public String bucket; //names are important
public int original;
public int available;
}
We have only 3 values in each of the objects.
Now, it's time to parse JSON into the written classes.
JsonPath path = JsonPath.from(json);
Pair[] pairs = path.getObject("$", Pair[].class);
Remember that Pair is a single JSON Object. That's why we start parsing from the root represented by dollar sign $ and we declare that JSON should be parsed into an ARRAY of Pair objects!
Now, processing will be much simpler!
I am not sure what do you need, but I will show you an example of how to get data from the buckets based on od_pair field and you should be able to figure out the rest of the processing.
So, we have the array of Pair class: Pair[] pairs;
Now, we want to get 1 Pair object based on od_pair value.
public static Pair getPairBasedOnOdPairValue(Pair[] pairs, String odPairValue) {
for (Pair pair : pairs) {
if (pair.od_pair.equals(odPairValue)) return pair;
}
throw new NoSuchElementException();
}
Now, we have the Pair object. We can access buckets for this object using
List<BucketObject> buckets = pair.buckets;
The rest of the processing is iterating over List<BucketObject> and getting desired values.
Hope it helps!
OP asked me to advise on how to fix his code, hence the second answer.
Let's analyze the code you provided:
public static void updateBuckets(String ServiceName, String DateOfJourney) throws Exception {
File jsonExample = new File(System.getProperty("user.dir"), "\\LogAvResponse\\LogAvResponse.json");
JsonPath jsonPath = new JsonPath(jsonExample);
List<Object> LegList = jsonPath.getList("$");
// List<HashMap<String, String>> jsonObjectsInArray = jsonPath.getList("$");
int NoofLegs = LegList.size();
System.out.println("No of legs :" + NoofLegs);
for (int j = 0; j <= NoofLegs; j++)
// for (HashMap<String, String> jsonObject : jsonObjectsInArray) {
{
String OD_Pair = jsonPath.param("j", j).getString("[j].od_pair");
// String OD_Pair = jsonObject.get("od_pair");
System.out.println("OD Pair: " + OD_Pair);
List<Object> BucketsList = jsonPath.param("j", j).getList("[j].buckets");
int NoOfBuckets = BucketsList.size();
// System.out.println("OD Pair: " + OD_Pair);
System.out.println("no of Buckets: " + NoOfBuckets);
for (int i = 0; i < NoOfBuckets; i++) {
String BucketCode = jsonPath.param("j", j).param("i", i).getString("[j].buckets[i].bucket");
String Available = jsonPath.param("j", j).param("i", i).getString("[j].buckets[i].available");
int BucketCodeColumn = XLUtils.getBucketCodeColumn(BucketCode);
int ServiceRow = XLUtils.getServiceRow(ServiceName, DateOfJourney, OD_Pair);
System.out.println("Row of " + ServiceName + ":" + DateOfJourney + "is:" + ServiceRow);
System.out.println("Bucket Code column of " + BucketCode + " is: " + BucketCodeColumn);
XLUtils.updateAvailability(ServiceRow, BucketCodeColumn, Available);
}
}
}
I am not using compilator right now, so I can miss a few things.
#1
First thing I can see is that you save the main array into the List<Object>
List<Object> LegList = jsonPath.getList("$");
Instead, you could save it to more understandable type, since Object is so generic, you have no idea what's inside it.
List<HashMap<String, Object>> LegList = jsonPath.getList("$");
#2
The for loop looks incorrect because of the evaluator
j <= NoofLegs;.
This will probably cause IndexArrayOutOfBoundsException or something similar. With the given code, if you have 4 legs, the for loop will try to process 5 legs which are incorrect.
#3
Similar to the #1, line where you save the bucket list
List<Object> BucketsList = jsonPath.param("j", j).getList("[j].buckets");
Could also be changed to List<HashMap<String, Object>> instead.
If you'd do that, you wouldn't need integer-based nested for loop.
You see, the HashMap<String, Object> is actually crucial to parse nested objects. The String is just a name like buckets or od_pair. It's the JSON representation. The second argument Object is different. RestAssured returns different types within the HashMap, that's why we use Object instead of String. Sometimes it's not String.
Example based on your JSON:
Collect buckets to List of HashMaps:
List<HashMap<String, Object>> bucketsList = jsonPath.param("j", j).getList("[j].buckets");
Each of the HashMap in the list is a representation of this:
{
"bucket":"C00",
"original":2,
"available":2
},
The Object in HashMap is either String or Integer in your case.
So, if you get element bucket from a HashMap you'll get its value.
Let's combine it with for loop for further clarification:
List<HashMap<String, Object>> bucketsList = jsonPath.param("j", j).getList("[j].buckets");
for (HashMap<String, Object> singleBucket : bucketsList) {
String firstValue = (String) singleBucket.get("bucket");
Integer secondValue = (Integer) singleBucket.get("original");
}
Looking at the error message, it looks like you are using rest-assured and that the JsonPath class is io.restassured.path.json.JsonPath from the rest-assured library.
I'm sure you're aware, but (perhaps for other readers) note that this is different from Jayway's json-path and is NOT the com.jayway.jsonpath.JsonPath class from that library.
Also be aware that, as mentioned in the documentation rest-assured uses the Groovy GPath syntax for manipulating/extracting JSON.
With that, I believe the following will extract what you need, i.e. od_pair and their corresponding buckets with available numbers:
Map<String, Map<String, Integer>> map = JsonPath.with(jsonString).get("collectEntries{entry -> [entry.od_pair, entry.buckets.collectEntries{bucketEntry -> [bucketEntry.bucket, bucketEntry.available]}]}");
where for each entry of the map, the key is the od_pair and the value is another map whose key is the bucket and value is the available number. The jsonString is the JSON you provided in the question.
You can iterate through the map to get what you want:
for(Map.Entry<String, Map<String, Integer>> entry : map.entrySet())
{
String od_pair = entry.getKey();
Map<String, Integer> bucketMap = entry.getValue();
for(Map.Entry<String, Integer> bucketEntry : bucketMap.entrySet())
{
String bucket = bucketEntry.getKey();
int available = bucketEntry.getValue();
}
}
Printing out the map you will get:
{7015400:8727100={C00=2, A01=0, B01=480}, 7015400:8814001={C00=2, A01=40, B01=672, B03=632, B05=558}}
Printing the map as JSON using Gson:
System.out.println(new GsonBuilder().setPrettyPrinting().create().toJson(map));
you will get
{
"7015400:8727100": {
"C00": 2,
"A01": 0,
"B01": 480
},
"7015400:8814001": {
"C00": 2,
"A01": 40,
"B01": 672,
"B03": 632,
"B05": 558
}
}
For background, the String collectEntries{entry -> [entry.od_pair, entry.buckets.collectEntries{bucketEntry -> [bucketEntry.bucket, bucketEntry.available]}]}
is a Groovy closure that uses methods from the Groovy Collections API: Refer Collection, List and Map
Shout out to #Fenio for the pure Java solution above.
The input to dictionary(fromTXTRecord:) comes from the network, potentially from outside the app, or even the device. However, Apple's docs say:
... Fails an assertion if txtData cannot be represented as an NSDictionary object.
Failing an assertion leaves the programmer (me) with no way of handling the error, which seems illogic for a method that processes external data.
If I run this in Terminal on a Mac:
dns-sd -R 'My Service Name' _myservice._tcp local 4567 asdf asdf
my app, running in an iPhone, crashes.
dictionary(fromTXTRecord:) expects the TXT record data (asdf asdf) to be in key=val form. If, like above, a word doesn't contain any = the method won't be able to parse it and fail the assertion.
I see no way of solving this problem other than not using that method at all and implementing my own parsing, which feels wrong.
Am I missing something?
Here's a solution in Swift 4.2, assuming the TXT record has only strings:
/// Decode the TXT record as a string dictionary, or [:] if the data is malformed
public func dictionary(fromTXTRecord txtData: Data) -> [String: String] {
var result = [String: String]()
var data = txtData
while !data.isEmpty {
// The first byte of each record is its length, so prefix that much data
let recordLength = Int(data.removeFirst())
guard data.count >= recordLength else { return [:] }
let recordData = data[..<(data.startIndex + recordLength)]
data = data.dropFirst(recordLength)
guard let record = String(bytes: recordData, encoding: .utf8) else { return [:] }
// The format of the entry is "key=value"
// (According to the reference implementation, = is optional if there is no value,
// and any equals signs after the first are part of the value.)
// `ommittingEmptySubsequences` is necessary otherwise an empty string will crash the next line
let keyValue = record.split(separator: "=", maxSplits: 1, omittingEmptySubsequences: false)
let key = String(keyValue[0])
// If there's no value, make the value the empty string
switch keyValue.count {
case 1:
result[key] = ""
case 2:
result[key] = String(keyValue[1])
default:
fatalError()
}
}
return result
}
I'm still hoping there's something I'm missing here, but in the mean time, I ended up checking the data for correctness and only then calling Apple's own method.
Here's my workaround:
func dictionaryFromTXTRecordData(data: NSData) -> [String:NSData] {
let buffer = UnsafeBufferPointer<UInt8>(start: UnsafePointer(data.bytes), count: data.length)
var pos = 0
while pos < buffer.count {
let len = Int(buffer[pos])
if len > (buffer.count - pos + 1) {
return [:]
}
let subdata = data.subdataWithRange(NSRange(location: pos + 1, length: len))
guard let substring = String(data: subdata, encoding: NSUTF8StringEncoding) else {
return [:]
}
if !substring.containsString("=") {
return [:]
}
pos = pos + len + 1
}
return NSNetService.dictionaryFromTXTRecordData(data)
}
I'm using Swift 2 here. All contributions are welcome. Swift 3 versions, Objective-C versions, improvements, corrections.
I just ran into this one using Swift 3. In my case the problem only occurred when I used NetService.dictionary(fromTXTRecord:) but did not occur when I switched to Objective-C and called NSNetService dictionaryFromTXTRecord:. When the Objective-C call encounters an entry without an equal sign it creates a key containing the data and shoves it into the dictionary with an NSNull value. From what I can tell the Swift version then enumerates that dictionary and throws a fit when it sees the NSNull. My solution was to add an Objective-C file and a utility function that calls dictionaryFromTXTRecord: and cleans up the results before handing them back to my Swift code.
I'm reading an NFC tag in my Adobe AIR mobile app. The data is read as a ByteArray, but I'm having difficulty pulling the full text. The sample text on the tag is "http://www.google.com"
Using this method, I get a portion of the String "http://www.goog", but not all of it. I'm assuming because each character is not a single byte:
private static function convertToString(byte_array : ByteArray) : String {
var arr : Array = [];
for (var i : Number = 1 ; i <= byte_array.bytesAvailable; i++) {
arr.push(byte_array.readUTFBytes(i));
}
var finalString : String = "";
for (var t : Number = 0; t < arr.length;t++) {
finalString = finalString + arr[t].toString();
}
return finalString;
}
I've also tried the method below, but it returns null:
bytes.readUTF();
I'm wondering if I need to convert the byteArray to a base64 string and then decode that. It seems like an extra step, but that's how I've done it before when sending data to/from a server using AMFPHP.
Thanks in advance for any input.
You could even simplify this code by simply calling
private static function convertToString(bytes:ByteArray):String {
bytes.position = 0;
var str:String = bytes.readUTFBytes(bytes.length);
return str;
}
This way you will read all contents of the bytearray in one single method call into your destination string.
Figured it out in the code below.
There were 2 errors, plus some cleanup:
private static function convertToString(bytes : ByteArray) : String {
bytes.position = 0;
var str : String = '';
while (bytes.bytesAvailable > 0) {
str += bytes.readUTFBytes(1);
}
return str;
}
the "bytesAvailable" property decreases as you read from the ByteArray. Here, I'm checking if the bytes > 0 instead of the length
the "readUTFBytes" method takes a length parameter (not position). Position is automatically updated as you read from the ByteArray. I'm passing in "1" instead of "i"