How would I declare a variable with a “+” or “-” sign in it? Javascript
I am making a program in Javascript but I am not sure how to declare a variable for grades with + and - in them.
var A+ = 4.0;
var A = 4.0;
var A- = 3.67;
javascript
asked Nov 13 '18 at 1:33
demdragons
207
add a comment |
I am making a program in Javascript but I am not sure how to declare a variable for grades with + and - in them.
var A+ = 4.0;
var A = 4.0;
var A- = 3.67;
javascript
asked Nov 13 '18 at 1:33
demdragons
207
add a comment |
I am making a program in Javascript but I am not sure how to declare a variable for grades with + and - in them.
var A+ = 4.0;
var A = 4.0;
var A- = 3.67;
javascript
asked Nov 13 '18 at 1:33
demdragons
207
I am making a program in Javascript but I am not sure how to declare a variable for grades with + and - in them.
var A+ = 4.0;
var A = 4.0;
var A- = 3.67;
javascript
javascript
asked Nov 13 '18 at 1:33
demdragons
207
asked Nov 13 '18 at 1:33
demdragons
207
edited Nov 14 '18 at 3:55
asked Nov 13 '18 at 1:33
demdragons
207
asked Nov 13 '18 at 1:33
demdragons
207
asked Nov 13 '18 at 1:33
demdragons
207
207
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
Those are illegal characters in variable names, but even if they weren't, this sounds like the perfect place for an object (a single variable), rather than multiple standalone variables, and the object can have the key-value pairs you're interested in:
const grades = {
'A+': 4,
'A': 4,
'A-': 3.67,
// ...
};
(Note that numbers with trailing decimal zeros have their trailing zeros truncated automatically - if you want to use 4.0, either use a string '4.0' instead, or use toFixed later, when retrieving the number, to convert to a string)
To iterate over such an object, use Object.entries to get each key-value pair:
Object.entries(grades).forEach(([key, val]) => {
// on first iteration, key will be A+, value will be 4
});
and to access or set properties on it, put the key names in brackets:
grades['A+'] = 'newA+Value';
(dot notation, such as grades.A, only works when the key follows the same rules as valid variable names - otherwise, have to use bracket notation)
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration ofObject.entries, the key will be a string containingA+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.
– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg ifvaluecontains theA+string, then you can get the number by doinggrades[value]
– CertainPerformance
Nov 14 '18 at 3:15
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
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active
oldest
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active
oldest
votes
Those are illegal characters in variable names, but even if they weren't, this sounds like the perfect place for an object (a single variable), rather than multiple standalone variables, and the object can have the key-value pairs you're interested in:
const grades = {
'A+': 4,
'A': 4,
'A-': 3.67,
// ...
};
(Note that numbers with trailing decimal zeros have their trailing zeros truncated automatically - if you want to use 4.0, either use a string '4.0' instead, or use toFixed later, when retrieving the number, to convert to a string)
To iterate over such an object, use Object.entries to get each key-value pair:
Object.entries(grades).forEach(([key, val]) => {
// on first iteration, key will be A+, value will be 4
});
and to access or set properties on it, put the key names in brackets:
grades['A+'] = 'newA+Value';
(dot notation, such as grades.A, only works when the key follows the same rules as valid variable names - otherwise, have to use bracket notation)
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration ofObject.entries, the key will be a string containingA+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.
– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg ifvaluecontains theA+string, then you can get the number by doinggrades[value]
– CertainPerformance
Nov 14 '18 at 3:15
add a comment |
Those are illegal characters in variable names, but even if they weren't, this sounds like the perfect place for an object (a single variable), rather than multiple standalone variables, and the object can have the key-value pairs you're interested in:
const grades = {
'A+': 4,
'A': 4,
'A-': 3.67,
// ...
};
(Note that numbers with trailing decimal zeros have their trailing zeros truncated automatically - if you want to use 4.0, either use a string '4.0' instead, or use toFixed later, when retrieving the number, to convert to a string)
To iterate over such an object, use Object.entries to get each key-value pair:
Object.entries(grades).forEach(([key, val]) => {
// on first iteration, key will be A+, value will be 4
});
and to access or set properties on it, put the key names in brackets:
grades['A+'] = 'newA+Value';
(dot notation, such as grades.A, only works when the key follows the same rules as valid variable names - otherwise, have to use bracket notation)
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration ofObject.entries, the key will be a string containingA+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.
– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg ifvaluecontains theA+string, then you can get the number by doinggrades[value]
– CertainPerformance
Nov 14 '18 at 3:15
add a comment |
Those are illegal characters in variable names, but even if they weren't, this sounds like the perfect place for an object (a single variable), rather than multiple standalone variables, and the object can have the key-value pairs you're interested in:
const grades = {
'A+': 4,
'A': 4,
'A-': 3.67,
// ...
};
(Note that numbers with trailing decimal zeros have their trailing zeros truncated automatically - if you want to use 4.0, either use a string '4.0' instead, or use toFixed later, when retrieving the number, to convert to a string)
To iterate over such an object, use Object.entries to get each key-value pair:
Object.entries(grades).forEach(([key, val]) => {
// on first iteration, key will be A+, value will be 4
});
and to access or set properties on it, put the key names in brackets:
grades['A+'] = 'newA+Value';
(dot notation, such as grades.A, only works when the key follows the same rules as valid variable names - otherwise, have to use bracket notation)
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
Those are illegal characters in variable names, but even if they weren't, this sounds like the perfect place for an object (a single variable), rather than multiple standalone variables, and the object can have the key-value pairs you're interested in:
const grades = {
'A+': 4,
'A': 4,
'A-': 3.67,
// ...
};
(Note that numbers with trailing decimal zeros have their trailing zeros truncated automatically - if you want to use 4.0, either use a string '4.0' instead, or use toFixed later, when retrieving the number, to convert to a string)
To iterate over such an object, use Object.entries to get each key-value pair:
Object.entries(grades).forEach(([key, val]) => {
// on first iteration, key will be A+, value will be 4
});
and to access or set properties on it, put the key names in brackets:
grades['A+'] = 'newA+Value';
(dot notation, such as grades.A, only works when the key follows the same rules as valid variable names - otherwise, have to use bracket notation)
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
answered Nov 13 '18 at 1:35
CertainPerformance
76.5k143862
76.5k143862
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration ofObject.entries, the key will be a string containingA+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.
– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg ifvaluecontains theA+string, then you can get the number by doinggrades[value]
– CertainPerformance
Nov 14 '18 at 3:15
add a comment |
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration ofObject.entries, the key will be a string containingA+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.
– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg ifvaluecontains theA+string, then you can get the number by doinggrades[value]
– CertainPerformance
Nov 14 '18 at 3:15
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
When attempting to use Object.entries, I get the same issue I had trying to declare the variables originally. It will not read it as "A+", separating the + from the A.
– demdragons
Nov 14 '18 at 2:39
In the first iteration of
Object.entries, the key will be a string containing A+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.– CertainPerformance
Nov 14 '18 at 2:41
In the first iteration of
Object.entries, the key will be a string containing A+, for example, which is perfectly valid - then, just use that string (and its value) for whatever you need it for.– CertainPerformance
Nov 14 '18 at 2:41
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
Okay, thank you. My last question would be how would I use this in a function, for example, if I used document.getElementById("grade1").value to get the inputted value from the textarea, say it was an A+. Would setting up these constants automatically turn that input into 4? Sorry for the confusion, I am just starting out with programming.
– demdragons
Nov 14 '18 at 3:13
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg if
value contains the A+ string, then you can get the number by doing grades[value]– CertainPerformance
Nov 14 '18 at 3:15
See the last part of the answer - to access or set properties on the object, just put the key names in brackets. eg if
value contains the A+ string, then you can get the number by doing grades[value]– CertainPerformance
Nov 14 '18 at 3:15
add a comment |
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