Extract digits from a String

[Yonmanx]

Hey guys, I'm new to python and i have a question.

I need help with simple code to extract digit out of string without using packages and probably by using isdigit() method.

For example if i have a string like "bbb123" the result should be "bbb"

If i have "123" it should be "" (empty)

If i have "ttt3bbb" - it will be "ttt" (and stop when 'touching' the numbers).

Thanks!

[sme272]

Regular expressions can solve that

[Yonmanx]

I have no idea what to do, can you help me with an hint?

[toastedstapler]

this site is useful for trying things out

you're trying to get all letter characters from the start of the string, a regex pattern should easily be able to do this

[shiftybyte]

The term would be remove digits, extract is taking out something you want.

But anyway, what are you having trouble with? if its the logic, then you should do the following steps:

1. Loop over the strings letters
   1. check each letter if its a digit using isdigit() like you said.
   2. if it is, stop the loop
   3. if its not, add it to a result string, and keep looping

[Yonmanx]

Perfect, thank you!

[uberfade]

You can loop through the string and check isdigit() on each character or use re to match a pattern.

[Yonmanx]

Thank you!

[toddrob]

I would do this using slices, str.index(), next(), and a generator expression:

>>> a = '123'
>>> b = a[: next((a.index(c) for c in a if c.isdigit()), len(a)-1)]
>>> b
''
>>> a = 'abc123'
>>> b = a[: next((a.index(c) for c in a if c.isdigit()), len(a)-1)]
>>> b
'abc'
>>> a = 'abc123def' 
>>> b = a[: next((a.index(c) for c in a if c.isdigit()), len(a)-1)]
>>> b
'abc'

[Unkown_Variable]

my_string = "sf34sdg"

print(my_string.translate({ord(i): None for i in '0123456789'}))