React calculator: check if any value exists in string
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0
down vote
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Is there anyway I could check if more than one value exists in a string? My idea is to have only two conditions:
a) if there´s no decimal, add it;
b) if there´s an operator (+-*/) followed by a number from 0 to 9, add it.
The decimal gets added only when one of those two conditions are met. What string method could I use?
handleDecimal(evt){
const result = evt.target.value;
let value = this.state.value;
if (value.indexOf('.') === -1){
this.setState(prevState => ({
value: this.state.value + result
}))};
}
javascript reactjs
asked Nov 11 at 7:01
Hernan Ariel
13216
add a comment |
up vote
0
down vote
favorite
Is there anyway I could check if more than one value exists in a string? My idea is to have only two conditions:
a) if there´s no decimal, add it;
b) if there´s an operator (+-*/) followed by a number from 0 to 9, add it.
The decimal gets added only when one of those two conditions are met. What string method could I use?
handleDecimal(evt){
const result = evt.target.value;
let value = this.state.value;
if (value.indexOf('.') === -1){
this.setState(prevState => ({
value: this.state.value + result
}))};
}
javascript reactjs
asked Nov 11 at 7:01
Hernan Ariel
13216
What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
Is there anyway I could check if more than one value exists in a string? My idea is to have only two conditions:
a) if there´s no decimal, add it;
b) if there´s an operator (+-*/) followed by a number from 0 to 9, add it.
The decimal gets added only when one of those two conditions are met. What string method could I use?
handleDecimal(evt){
const result = evt.target.value;
let value = this.state.value;
if (value.indexOf('.') === -1){
this.setState(prevState => ({
value: this.state.value + result
}))};
}
javascript reactjs
asked Nov 11 at 7:01
Hernan Ariel
13216
Is there anyway I could check if more than one value exists in a string? My idea is to have only two conditions:
a) if there´s no decimal, add it;
b) if there´s an operator (+-*/) followed by a number from 0 to 9, add it.
The decimal gets added only when one of those two conditions are met. What string method could I use?
handleDecimal(evt){
const result = evt.target.value;
let value = this.state.value;
if (value.indexOf('.') === -1){
this.setState(prevState => ({
value: this.state.value + result
}))};
}
javascript reactjs
javascript reactjs
asked Nov 11 at 7:01
Hernan Ariel
13216
asked Nov 11 at 7:01
Hernan Ariel
13216
asked Nov 11 at 7:01
Hernan Ariel
13216
asked Nov 11 at 7:01
Hernan Ariel
13216
asked Nov 11 at 7:01
Hernan Ariel
13216
13216
What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07
add a comment |
What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07
What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
You can use a regular expression and String.prototype.search() to accomplish this.
The RegEx /([-+*/]d)/ will match an operator followed by any digit.
If you want to add a decimal even when there exists a decimal, but there is also an operator followed by a number:
if (value.indexOf === '-1' || value.search(/([-+*/]d)/) > -1) { //add decimal }
If you want to have only one decimal at most in the final string:
if (value.indexOf === '-1') {
//add decimal
} else if (value.search(/([-+*/]d)/) > -1) {
//add decimal
}
answered Nov 11 at 14:25
Syed Rashid
262
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
You can use a regular expression and String.prototype.search() to accomplish this.
The RegEx /([-+*/]d)/ will match an operator followed by any digit.
If you want to add a decimal even when there exists a decimal, but there is also an operator followed by a number:
if (value.indexOf === '-1' || value.search(/([-+*/]d)/) > -1) { //add decimal }
If you want to have only one decimal at most in the final string:
if (value.indexOf === '-1') {
//add decimal
} else if (value.search(/([-+*/]d)/) > -1) {
//add decimal
}
answered Nov 11 at 14:25
Syed Rashid
262
add a comment |
up vote
1
down vote
accepted
You can use a regular expression and String.prototype.search() to accomplish this.
The RegEx /([-+*/]d)/ will match an operator followed by any digit.
If you want to add a decimal even when there exists a decimal, but there is also an operator followed by a number:
if (value.indexOf === '-1' || value.search(/([-+*/]d)/) > -1) { //add decimal }
If you want to have only one decimal at most in the final string:
if (value.indexOf === '-1') {
//add decimal
} else if (value.search(/([-+*/]d)/) > -1) {
//add decimal
}
answered Nov 11 at 14:25
Syed Rashid
262
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
You can use a regular expression and String.prototype.search() to accomplish this.
The RegEx /([-+*/]d)/ will match an operator followed by any digit.
If you want to add a decimal even when there exists a decimal, but there is also an operator followed by a number:
if (value.indexOf === '-1' || value.search(/([-+*/]d)/) > -1) { //add decimal }
If you want to have only one decimal at most in the final string:
if (value.indexOf === '-1') {
//add decimal
} else if (value.search(/([-+*/]d)/) > -1) {
//add decimal
}
answered Nov 11 at 14:25
Syed Rashid
262
You can use a regular expression and String.prototype.search() to accomplish this.
The RegEx /([-+*/]d)/ will match an operator followed by any digit.
If you want to add a decimal even when there exists a decimal, but there is also an operator followed by a number:
if (value.indexOf === '-1' || value.search(/([-+*/]d)/) > -1) { //add decimal }
If you want to have only one decimal at most in the final string:
if (value.indexOf === '-1') {
//add decimal
} else if (value.search(/([-+*/]d)/) > -1) {
//add decimal
}
answered Nov 11 at 14:25
Syed Rashid
262
edited Nov 11 at 14:35
answered Nov 11 at 14:25
Syed Rashid
262
answered Nov 11 at 14:25
Syed Rashid
262
answered Nov 11 at 14:25
Syed Rashid
262
262
add a comment |
add a comment |
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What exactly do you mean, "add it"? Do you mean add some numbers together, or insert a decimal point (at what position?), or what? Can you give a couple of examples?
– CertainPerformance
Nov 11 at 7:03
In the current handle event, if the decimal isn´t there, the decimal gets added. I want something similar to that, but the condition should be something like "set the state with a decimal only if the decimal doesn´t exist already OR if there´s an operator followed by a number". For instance: if the string is "2322399838", you can add a decimal to it (just one). If, after that, there´s a "+2293998" you can add another decimal and so on. Hopefully I´m being clear.
– Hernan Ariel
Nov 11 at 7:07