getting only the first Number from String in Python

Question

I´m currently facing the problem that I have a string of which I want to extract only the first number. My first step was to extract the numbers from the string.

Headline = "redirectDetail('27184','2 -New-York-Explorer-Pass')"
print (re.findall('\d+', headline ))
Output is ['27184', '2']

In this case it returned me two numbers but I only want to have the first one "27184".

Hence, I tried with the following code:

 print (re.findall('/^[^\d]*(\d+)/', headline ))

But It does not work:

 Output:[]

Can you guys help me out? Any feedback is appreciated

You're using findall, which finds all the occurrences. By the way, Python regular expressions do not require / characters. — Andrea Corbellini
– Andrea Corbellini, Commented Sep 14, 2015 at 18:22

Avinash Raj · Accepted Answer · 2015-09-14 18:19:15Z

67

Just use re.search which stops matching once it finds a match.

re.search(r'\d+', headline).group()

or

You must remove the forward slashes present in your regex.

re.findall(r'^\D*(\d+)', headline)

answered Sep 14, 2015 at 18:19

Avinash Raj

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Dylan Lawrence · Accepted Answer · 2015-09-14 18:23:06Z

5

re.search('[0-9]+', headline).group()

answered Sep 14, 2015 at 18:23

Dylan Lawrence

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David · Accepted Answer · 2015-09-14 18:55:19Z

5

Solution without regex (not necessarily better):

import string

no_digits = string.printable[10:]

headline = "redirectDetail('27184','2 -New-York-Explorer-Pass')"
trans = str.maketrans(no_digits, " "*len(no_digits))

print(headline.translate(trans).split()[0])
>>> 27184

answered Sep 14, 2015 at 18:55

David

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Comments

Mahmoud Magdy · Accepted Answer · 2021-06-15 17:40:36Z

In my case I wanted to get the first number in the string and the currency too, I tried all solutions, some returned the number without a dot, others returned the number I did like this

priceString = "Rs249.5"

def advancedSplit(unformatedtext):
    custom_numbers = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
    priceList = []
    str_length = len(unformatedtext)
    index = 0
    for l in range(len(unformatedtext)):
        if unformatedtext[l] in custom_numbers:
            price = unformatedtext[slice(l, len(unformatedtext))]
            currency = unformatedtext[slice(0,l)]
            priceList.append(currency)
            priceList.append(price)
            break
        elif index == str_length:
            priceList.append("")
            priceList.append("unformatedtext")
            break
        else:
            continue
            
        index += 1
    return priceList
print(advancedSplit(priceString))

to make sure the list will always has len of 2 I added the elif in case the priceString was just "249.5" because I'm using this in web scrape

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