How to add condition to this Regex?

Question

How to add a condition where if the first character is 4 then 16 digits and if 3 then 15 digits?

this is what i tried so far:

<ion-input
            ngModel name="CNumber"
            required 
            (ionChange)="C_number($event.target.value)" 
            (ionInput)="C_number($event.target.value)"  
            maxlength="{{Maxlength}}"
            type="tel"
            pattern="^(4)[0-9]{15}$"
            >

^(4)[0-9]{15}

this will accept if the first is 4 and allows 16 characters, but how to add starting digit 3 and when so it accepts 15 characters only?

Use an alternation `^(?:4[0-9]{15}|3[0-9]{14})$` matching either one of the options. https://regex101.com/r/xw2biW/1 — The fourth bird, Sep 04 '19 at 06:46

score 0 · Accepted Answer · answered Sep 04 '19 at 06:49

0

I'd try simple.alternative:

^((4)[0-9]{15})|((3)[0-9]{14})$

answered Sep 04 '19 at 06:49

mrzasa

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what if i want it to also accept space " ". – Omar .K Sep 17 '19 at 10:39
you can experiment here: https://regex101.com/r/qH52Xr/1 – mrzasa Sep 17 '19 at 10:42

How to add condition to this Regex?

1 Answers1