regex with replace() for letters only

user_2805507 0
Viewed 2589

I have a string that output

20153 Risk

What i am trying to achieve is getting only letters, i have achieved by getting only numbers using regular expression which is

const cf_regex_number = cf_input.replace(/\D/g, '');

this will return only 20153 . But as soon as i tried to only get letters , its returning the while string instead of Risk . i have done my research and the regular expression to get only letters is using **/^[a-zA-Z]*$/**

This is my line of code i tried to get only letters

const cf_regex_character = cf_input.replace(/^[a-zA-Z]*$/,'')

but instead of returning Risk , it is returning 20153 Risk which is the whole line of string .

text replace javascript regex
3 Answers

/[^a-z]+/i

  • The [ brackets ] signify a range of characters; specifically, a to z in this case.

  • Actually the i flag means insensitive to case, so that includes A to Z also.

  • The caret ^ inverts the pattern; it means, anything not in the specified range.

  • And the + means continue adding characters to the match as long as they are they within that range.

  • Then stop matching.

In effect this matches everything up to the space in 20153 Risk.

Then you replace this match with the empty string '' and what you've got left is Risk.

const string = '20153 Risk';
const result = string.replace(/[^a-z]+/i, '');
console.log(result);

user_133782470

Your first pattern is locating every non-digit and replacing it with nothing.

On the other hand, your second pattern is locating just the first occurence of a pattern, and the pattern is looking for start of string, followed by letters, followed by end of string. There is no such sequence - if you start from the start of string, there are exactly zero letters, and then you are left very far from the expected end of the string. Even if that worked, you are deleting letters, not non-letters.

This pattern is parallel to your first one (delete any occurence of a non-letter):

const cf_regex_character = cf_input.replace(/[^a-zA-Z]/g,'')

but possibly a better way to go is to extract the desired substring, instead of deleting everything that it is not:

const letters = cf_input.match(/[a-z]+/i)[0];
const numbers = cf_input.match(/\d+/)[0];

(This is if you know there is such a substring; if you are unsure it would be better to code a bit more defensively.)

user_2404430 

cf_input="20153 Risk"

const cf_regex_character = cf_input.replace(/\d+\s/,'')
console.log(cf_regex_character)

str="20153 Risk"
reg=/[a-z]+/gi
res=str.match(reg)
console.log(res[0])

user_99220110
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