Regex to match words in a sentence by its prefix
I have this regex on mongodb query to match words by prefix:
{sentence: new RegExp('^'+key,'gi')}
What would be the right regex pattern if I want it to match a sentence that has at least a word starting with key prefix? For example:
If I have a sentence
"This is a dog"
when key is 'do', then it should match that sentence since prefix 'do' is a substring of 'dog'.
My solution as of now only works for the first word of the sentence. It so far only matches that sentence if I type in 't' or 'th' or 'this'. It wouldnt match that sentence whenever I type in 'i' (prefix for 'is') or 'do' (prefix for 'dog').
javascript regex mongodb
edited Jan 29 '12 at 9:22
gdoron
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
add a comment |
I have this regex on mongodb query to match words by prefix:
{sentence: new RegExp('^'+key,'gi')}
What would be the right regex pattern if I want it to match a sentence that has at least a word starting with key prefix? For example:
If I have a sentence
"This is a dog"
when key is 'do', then it should match that sentence since prefix 'do' is a substring of 'dog'.
My solution as of now only works for the first word of the sentence. It so far only matches that sentence if I type in 't' or 'th' or 'this'. It wouldnt match that sentence whenever I type in 'i' (prefix for 'is') or 'do' (prefix for 'dog').
javascript regex mongodb
edited Jan 29 '12 at 9:22
gdoron
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
add a comment |
I have this regex on mongodb query to match words by prefix:
{sentence: new RegExp('^'+key,'gi')}
What would be the right regex pattern if I want it to match a sentence that has at least a word starting with key prefix? For example:
If I have a sentence
"This is a dog"
when key is 'do', then it should match that sentence since prefix 'do' is a substring of 'dog'.
My solution as of now only works for the first word of the sentence. It so far only matches that sentence if I type in 't' or 'th' or 'this'. It wouldnt match that sentence whenever I type in 'i' (prefix for 'is') or 'do' (prefix for 'dog').
javascript regex mongodb
edited Jan 29 '12 at 9:22
gdoron
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
I have this regex on mongodb query to match words by prefix:
{sentence: new RegExp('^'+key,'gi')}
What would be the right regex pattern if I want it to match a sentence that has at least a word starting with key prefix? For example:
If I have a sentence
"This is a dog"
when key is 'do', then it should match that sentence since prefix 'do' is a substring of 'dog'.
My solution as of now only works for the first word of the sentence. It so far only matches that sentence if I type in 't' or 'th' or 'this'. It wouldnt match that sentence whenever I type in 'i' (prefix for 'is') or 'do' (prefix for 'dog').
javascript regex mongodb
javascript regex mongodb
edited Jan 29 '12 at 9:22
gdoron
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
edited Jan 29 '12 at 9:22
gdoron
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
edited Jan 29 '12 at 9:22
gdoron
110k41247309
edited Jan 29 '12 at 9:22
gdoron
110k41247309
edited Jan 29 '12 at 9:22
gdoron
110k41247309
110k41247309
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
asked Jan 29 '12 at 9:20
Benny TjiaBenny Tjia
3,734103147
3,734103147
add a comment |
add a comment |
4 Answers
4
active
oldest
votes
Use the b anchor to match word boundaries:
bdo
finds 'do' in 'nice dog', but doesn't match 'much ado about nothing'.
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:'\bdo'.
– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
add a comment |
You can use the expression /bprefixw+/. This should match any word starting with "prefix". Here the b represents a word boundary and w is any word character.
If you don't want to get the whole word, you can just do /bprefix/. If you want to put this in a string, you also have to escape the : '\bprefix'.
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
1
Do you need thebafterw+? Surely the word boundary isn't a word character...
– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
add a comment |
The other answers suggesting the word boundary matching are neat, but will mean that an index isn't used efficiently. If you need fast lookups, you might want to consider adding a field "words" with each of your words broken up, i.e.
{sentence: "This is a dog",
words: ["This", "is", "a", "dog"]}
After putting an index on the words field, you can go back to using:
{words: new RegExp('^'+key,'gi')}
and a key of "do" will now match this object and use an index.
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
add a comment |
^ matches beginning of the string (or beginning of a line if the multiline flag is set).
b matches a word boundary.
bdo matches words beginning with "do".
So for your example:
{sentence: new RegExp('\b'+key,'gi')}
(Noting that in a JavaScript string you have to escape backslashes.)
If you will be needing to capture the match(es) to find out what word(s) matched the pattern you'll want to wrap the expression in parentheses and add a bit to match the rest of the word:
new RegExp('(\b' + key + '\w*)','gi')
Where w is any word character and the * is zero or more. If you want words that have at least one character more than the key then use + instead of *.
See the many regex guides on the web for more details, e.g., https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
Use the b anchor to match word boundaries:
bdo
finds 'do' in 'nice dog', but doesn't match 'much ado about nothing'.
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:'\bdo'.
– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
add a comment |
Use the b anchor to match word boundaries:
bdo
finds 'do' in 'nice dog', but doesn't match 'much ado about nothing'.
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:'\bdo'.
– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
add a comment |
Use the b anchor to match word boundaries:
bdo
finds 'do' in 'nice dog', but doesn't match 'much ado about nothing'.
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
Use the b anchor to match word boundaries:
bdo
finds 'do' in 'nice dog', but doesn't match 'much ado about nothing'.
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
answered Jan 29 '12 at 9:23
wutzwutz
2,8691113
2,8691113
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:'\bdo'.
– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
add a comment |
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:'\bdo'.
– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
5
5
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:
'\bdo'.– Tikhon Jelvis
Jan 29 '12 at 9:25
If you're actually going to have it in a string (as opposed to a regex literal) you should escape the backslash:
'\bdo'.– Tikhon Jelvis
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
Good point, thanks
– wutz
Jan 29 '12 at 9:25
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
thanks for the help. I upvoted all the answers since they are all correct. I dont know which one to accept, so I go with the earliest :)
– Benny Tjia
Jan 29 '12 at 9:42
add a comment |
You can use the expression /bprefixw+/. This should match any word starting with "prefix". Here the b represents a word boundary and w is any word character.
If you don't want to get the whole word, you can just do /bprefix/. If you want to put this in a string, you also have to escape the : '\bprefix'.
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
1
Do you need thebafterw+? Surely the word boundary isn't a word character...
– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
add a comment |
You can use the expression /bprefixw+/. This should match any word starting with "prefix". Here the b represents a word boundary and w is any word character.
If you don't want to get the whole word, you can just do /bprefix/. If you want to put this in a string, you also have to escape the : '\bprefix'.
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
1
Do you need thebafterw+? Surely the word boundary isn't a word character...
– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
add a comment |
You can use the expression /bprefixw+/. This should match any word starting with "prefix". Here the b represents a word boundary and w is any word character.
If you don't want to get the whole word, you can just do /bprefix/. If you want to put this in a string, you also have to escape the : '\bprefix'.
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
You can use the expression /bprefixw+/. This should match any word starting with "prefix". Here the b represents a word boundary and w is any word character.
If you don't want to get the whole word, you can just do /bprefix/. If you want to put this in a string, you also have to escape the : '\bprefix'.
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
edited Jan 29 '12 at 9:33
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
answered Jan 29 '12 at 9:23
Tikhon JelvisTikhon Jelvis
55.5k16153194
55.5k16153194
1
Do you need thebafterw+? Surely the word boundary isn't a word character...
– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
add a comment |
1
Do you need thebafterw+? Surely the word boundary isn't a word character...
– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
1
1
Do you need the
b after w+? Surely the word boundary isn't a word character...– nnnnnn
Jan 29 '12 at 9:32
Do you need the
b after w+? Surely the word boundary isn't a word character...– nnnnnn
Jan 29 '12 at 9:32
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
@nnnnnn Yeah, you're right.
– Tikhon Jelvis
Jan 29 '12 at 9:33
add a comment |
The other answers suggesting the word boundary matching are neat, but will mean that an index isn't used efficiently. If you need fast lookups, you might want to consider adding a field "words" with each of your words broken up, i.e.
{sentence: "This is a dog",
words: ["This", "is", "a", "dog"]}
After putting an index on the words field, you can go back to using:
{words: new RegExp('^'+key,'gi')}
and a key of "do" will now match this object and use an index.
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
add a comment |
The other answers suggesting the word boundary matching are neat, but will mean that an index isn't used efficiently. If you need fast lookups, you might want to consider adding a field "words" with each of your words broken up, i.e.
{sentence: "This is a dog",
words: ["This", "is", "a", "dog"]}
After putting an index on the words field, you can go back to using:
{words: new RegExp('^'+key,'gi')}
and a key of "do" will now match this object and use an index.
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
add a comment |
The other answers suggesting the word boundary matching are neat, but will mean that an index isn't used efficiently. If you need fast lookups, you might want to consider adding a field "words" with each of your words broken up, i.e.
{sentence: "This is a dog",
words: ["This", "is", "a", "dog"]}
After putting an index on the words field, you can go back to using:
{words: new RegExp('^'+key,'gi')}
and a key of "do" will now match this object and use an index.
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
The other answers suggesting the word boundary matching are neat, but will mean that an index isn't used efficiently. If you need fast lookups, you might want to consider adding a field "words" with each of your words broken up, i.e.
{sentence: "This is a dog",
words: ["This", "is", "a", "dog"]}
After putting an index on the words field, you can go back to using:
{words: new RegExp('^'+key,'gi')}
and a key of "do" will now match this object and use an index.
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
answered Jan 30 '12 at 7:15
Nic CottrellNic Cottrell
5,36233154
5,36233154
add a comment |
add a comment |
^ matches beginning of the string (or beginning of a line if the multiline flag is set).
b matches a word boundary.
bdo matches words beginning with "do".
So for your example:
{sentence: new RegExp('\b'+key,'gi')}
(Noting that in a JavaScript string you have to escape backslashes.)
If you will be needing to capture the match(es) to find out what word(s) matched the pattern you'll want to wrap the expression in parentheses and add a bit to match the rest of the word:
new RegExp('(\b' + key + '\w*)','gi')
Where w is any word character and the * is zero or more. If you want words that have at least one character more than the key then use + instead of *.
See the many regex guides on the web for more details, e.g., https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
add a comment |
^ matches beginning of the string (or beginning of a line if the multiline flag is set).
b matches a word boundary.
bdo matches words beginning with "do".
So for your example:
{sentence: new RegExp('\b'+key,'gi')}
(Noting that in a JavaScript string you have to escape backslashes.)
If you will be needing to capture the match(es) to find out what word(s) matched the pattern you'll want to wrap the expression in parentheses and add a bit to match the rest of the word:
new RegExp('(\b' + key + '\w*)','gi')
Where w is any word character and the * is zero or more. If you want words that have at least one character more than the key then use + instead of *.
See the many regex guides on the web for more details, e.g., https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
add a comment |
^ matches beginning of the string (or beginning of a line if the multiline flag is set).
b matches a word boundary.
bdo matches words beginning with "do".
So for your example:
{sentence: new RegExp('\b'+key,'gi')}
(Noting that in a JavaScript string you have to escape backslashes.)
If you will be needing to capture the match(es) to find out what word(s) matched the pattern you'll want to wrap the expression in parentheses and add a bit to match the rest of the word:
new RegExp('(\b' + key + '\w*)','gi')
Where w is any word character and the * is zero or more. If you want words that have at least one character more than the key then use + instead of *.
See the many regex guides on the web for more details, e.g., https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
^ matches beginning of the string (or beginning of a line if the multiline flag is set).
b matches a word boundary.
bdo matches words beginning with "do".
So for your example:
{sentence: new RegExp('\b'+key,'gi')}
(Noting that in a JavaScript string you have to escape backslashes.)
If you will be needing to capture the match(es) to find out what word(s) matched the pattern you'll want to wrap the expression in parentheses and add a bit to match the rest of the word:
new RegExp('(\b' + key + '\w*)','gi')
Where w is any word character and the * is zero or more. If you want words that have at least one character more than the key then use + instead of *.
See the many regex guides on the web for more details, e.g., https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
edited Jan 29 '12 at 9:31
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
answered Jan 29 '12 at 9:25
nnnnnnnnnnnn
124k18144198
124k18144198
add a comment |
add a comment |
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