Can someone please explain in plain english what is going on in a particular part of my code for objects?
although it is a very simple code, I would like to get a full understanding of what is happening in my condition:
let getFreqOn = function(string){
//set a variable for object
let object = {}
for (let key = 0; key < string.length; key++){
// if (object.hasOwnProperty(string[key])) {
// if (object[string[key]]) {
// if (object[string[key]] !== undefined) {
if (string[key] in object) {
object[string[key]]++
}
else{
object[string[key]] = 1
}
}
return object
}
My main concern would be the first condition, I understand what it is they do but I cant put in to plain English how it is working. For example if (string[key] in object) is basically telling my that if a specific property is in the empty object I defined, then I will set then it will be set as the property and incremented. But what I'm trying to wrap my head around is that the object is empty, so how can the property be in the object?
Hoping someone can enlighten me on the conditions that I commented out as well. Sorry for the noob question.
javascript object properties key javascript-objects
edited Nov 20 '18 at 21:10
Pointy
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
add a comment |
although it is a very simple code, I would like to get a full understanding of what is happening in my condition:
let getFreqOn = function(string){
//set a variable for object
let object = {}
for (let key = 0; key < string.length; key++){
// if (object.hasOwnProperty(string[key])) {
// if (object[string[key]]) {
// if (object[string[key]] !== undefined) {
if (string[key] in object) {
object[string[key]]++
}
else{
object[string[key]] = 1
}
}
return object
}
My main concern would be the first condition, I understand what it is they do but I cant put in to plain English how it is working. For example if (string[key] in object) is basically telling my that if a specific property is in the empty object I defined, then I will set then it will be set as the property and incremented. But what I'm trying to wrap my head around is that the object is empty, so how can the property be in the object?
Hoping someone can enlighten me on the conditions that I commented out as well. Sorry for the noob question.
javascript object properties key javascript-objects
edited Nov 20 '18 at 21:10
Pointy
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
Your question is exactly what thatiftest is about.
– Pointy
Nov 20 '18 at 21:11
add a comment |
although it is a very simple code, I would like to get a full understanding of what is happening in my condition:
let getFreqOn = function(string){
//set a variable for object
let object = {}
for (let key = 0; key < string.length; key++){
// if (object.hasOwnProperty(string[key])) {
// if (object[string[key]]) {
// if (object[string[key]] !== undefined) {
if (string[key] in object) {
object[string[key]]++
}
else{
object[string[key]] = 1
}
}
return object
}
My main concern would be the first condition, I understand what it is they do but I cant put in to plain English how it is working. For example if (string[key] in object) is basically telling my that if a specific property is in the empty object I defined, then I will set then it will be set as the property and incremented. But what I'm trying to wrap my head around is that the object is empty, so how can the property be in the object?
Hoping someone can enlighten me on the conditions that I commented out as well. Sorry for the noob question.
javascript object properties key javascript-objects
edited Nov 20 '18 at 21:10
Pointy
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
although it is a very simple code, I would like to get a full understanding of what is happening in my condition:
let getFreqOn = function(string){
//set a variable for object
let object = {}
for (let key = 0; key < string.length; key++){
// if (object.hasOwnProperty(string[key])) {
// if (object[string[key]]) {
// if (object[string[key]] !== undefined) {
if (string[key] in object) {
object[string[key]]++
}
else{
object[string[key]] = 1
}
}
return object
}
My main concern would be the first condition, I understand what it is they do but I cant put in to plain English how it is working. For example if (string[key] in object) is basically telling my that if a specific property is in the empty object I defined, then I will set then it will be set as the property and incremented. But what I'm trying to wrap my head around is that the object is empty, so how can the property be in the object?
Hoping someone can enlighten me on the conditions that I commented out as well. Sorry for the noob question.
javascript object properties key javascript-objects
javascript object properties key javascript-objects
edited Nov 20 '18 at 21:10
Pointy
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
edited Nov 20 '18 at 21:10
Pointy
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
edited Nov 20 '18 at 21:10
Pointy
315k44454514
edited Nov 20 '18 at 21:10
Pointy
315k44454514
edited Nov 20 '18 at 21:10
Pointy
315k44454514
315k44454514
asked Nov 20 '18 at 21:10
TerryTerry
161
asked Nov 20 '18 at 21:10
TerryTerry
161
asked Nov 20 '18 at 21:10
TerryTerry
161
161
Your question is exactly what thatiftest is about.
– Pointy
Nov 20 '18 at 21:11
add a comment |
Your question is exactly what thatiftest is about.
– Pointy
Nov 20 '18 at 21:11
Your question is exactly what that
if test is about.– Pointy
Nov 20 '18 at 21:11
Your question is exactly what that
if test is about.– Pointy
Nov 20 '18 at 21:11
add a comment |
1 Answer
1
active
oldest
votes
First, the in operator returns a boolean result. It checks whether the string on the left is present as a property name in the object on the right.
Thus
if (string[key] in object)
asks whether that single character of the string is in use as a property name in the object. As you observed, the very first time through the loop that cannot possibly be true, because the object starts off empty.
Thus the if test is false, so the else part runs. There, the code still refers to object[string[key]], but it's a simple assignment. An assignment to an object property works whether or not the property name is already there; when it isn't, a new object property is implicitly created.
The key difference is right there in the two different statements from the two parts of the if - else:
object[string[key]]++; // only works when property exists
object[string[key]] = 1; // works always
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
First, the in operator returns a boolean result. It checks whether the string on the left is present as a property name in the object on the right.
Thus
if (string[key] in object)
asks whether that single character of the string is in use as a property name in the object. As you observed, the very first time through the loop that cannot possibly be true, because the object starts off empty.
Thus the if test is false, so the else part runs. There, the code still refers to object[string[key]], but it's a simple assignment. An assignment to an object property works whether or not the property name is already there; when it isn't, a new object property is implicitly created.
The key difference is right there in the two different statements from the two parts of the if - else:
object[string[key]]++; // only works when property exists
object[string[key]] = 1; // works always
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
add a comment |
First, the in operator returns a boolean result. It checks whether the string on the left is present as a property name in the object on the right.
Thus
if (string[key] in object)
asks whether that single character of the string is in use as a property name in the object. As you observed, the very first time through the loop that cannot possibly be true, because the object starts off empty.
Thus the if test is false, so the else part runs. There, the code still refers to object[string[key]], but it's a simple assignment. An assignment to an object property works whether or not the property name is already there; when it isn't, a new object property is implicitly created.
The key difference is right there in the two different statements from the two parts of the if - else:
object[string[key]]++; // only works when property exists
object[string[key]] = 1; // works always
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
add a comment |
First, the in operator returns a boolean result. It checks whether the string on the left is present as a property name in the object on the right.
Thus
if (string[key] in object)
asks whether that single character of the string is in use as a property name in the object. As you observed, the very first time through the loop that cannot possibly be true, because the object starts off empty.
Thus the if test is false, so the else part runs. There, the code still refers to object[string[key]], but it's a simple assignment. An assignment to an object property works whether or not the property name is already there; when it isn't, a new object property is implicitly created.
The key difference is right there in the two different statements from the two parts of the if - else:
object[string[key]]++; // only works when property exists
object[string[key]] = 1; // works always
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
First, the in operator returns a boolean result. It checks whether the string on the left is present as a property name in the object on the right.
Thus
if (string[key] in object)
asks whether that single character of the string is in use as a property name in the object. As you observed, the very first time through the loop that cannot possibly be true, because the object starts off empty.
Thus the if test is false, so the else part runs. There, the code still refers to object[string[key]], but it's a simple assignment. An assignment to an object property works whether or not the property name is already there; when it isn't, a new object property is implicitly created.
The key difference is right there in the two different statements from the two parts of the if - else:
object[string[key]]++; // only works when property exists
object[string[key]] = 1; // works always
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
answered Nov 20 '18 at 21:15
PointyPointy
315k44454514
315k44454514
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
add a comment |
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
Makes perfect sense. Thanks so much!!!
– Terry
Nov 20 '18 at 21:35
add a comment |
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Your question is exactly what that
iftest is about.– Pointy
Nov 20 '18 at 21:11