How to extract numbers (year) from string?

Question

I have sample strings, and I have to extract the year from pandas Dataframe. I am unsure of how to do it? I tried using the pandas extract method using regular expression but I am unsuccessful.

Input:

Césio 137 - O Pesadelo de Goiânia (1990)

Nattbuss 807 (1997)

Νόμος 4000 (1962)

Output:

I have tried using the following regex: \d\d\d\d

But in the expression, Νόμος 4000 (1962), I am not getting my expected result. I want to only extract 1962, not 4000.

I am aiming to extract the year from the expressions given.

Thanks in advance.

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Please give a [mre] of what was unsuccessful. You can also read https://stackoverflow.com/q/4736/3001761 — jonrsharpe, Feb 05 '21 at 18:32
My sincere apologies. I have updated my issue. I shall make sure that it won't be repeated. — SAI SRIKAR, Feb 05 '21 at 18:40
From the duplicate `df['col'].str.extract('.*\((.*)\).*')` if the duplicate answer, is helpful, be sure to upvote it. — Trenton McKinney, Feb 05 '21 at 19:44

score 0 · Answer 1 · answered Feb 05 '21 at 18:44

It is a very simple regex.

df = pd.read_csv(io.StringIO("""Césio 137 - O Pesadelo de Goiânia (1990)
Nattbuss 807 (1997)
Νόμος 4000 (1962)"""), names=["input"])

myre = re.compile(".*\(([0-9]+)\).*")
df.assign(output=df.input.str.extract(myre))

output

	input	output
0	Césio 137 - O Pesadelo de Goiânia (1990)	1990
1	Nattbuss 807 (1997)	1997
2	Νόμος 4000 (1962)	1962

score 0 · Answer 2 · answered Feb 05 '21 at 18:45

This should help:

strings = ["Césio 137 - O Pesadelo de Goiânia (1990)", "Nattbuss 807 (1997)", "Νόμος 4000 (1962)"]

for string in strings:
    str = string.split(" ")
    last = len(str) - 1
    print(str[last].replace("(","").replace(")",""))

Result:

1990
1997
1962

How to extract numbers (year) from string?

2 Answers2

output