Pandas: Extract only non alphanumeric characters from the specified column of a given DataFrame

Last update on May 28 2022 13:02:34 (UTC/GMT +8 hours)

Pandas: String and Regular Expression Exercise-30 with Solution

Write a Pandas program to extract only non alphanumeric characters from the specified column of a given DataFrame.

Sample Solution:

Python Code :

import pandas as pd
import re as re
pd.set_option('display.max_columns', 10)
df = pd.DataFrame({
    'company_code': ['c0001#','[email protected]^2','$c0003', 'c0003', '&c0004'],
    'year': ['year 1800','year 1700','year 2300', 'year 1900', 'year 2200']
    })
print("Original DataFrame:")
print(df)
def find_nonalpha(text):
    result = re.findall("[^A-Za-z0-9 ]",text)
    return result
df['nonalpha']=df['company_code'].apply(lambda x: find_nonalpha(x))
print("\Extracting only non alphanumeric characters from company_code:")
print(df)

Sample Output:

Original DataFrame:
  company_code       year
0       c0001#  year 1800
1      [email protected]^2  year 1700
2       $c0003  year 2300
3        c0003  year 1900
4       &c0004  year 2200
\Extracting only non alphanumeric characters from company_code:
  company_code       year nonalpha
0       c0001#  year 1800      [#]
1      [email protected]^2  year 1700   [@, ^]
2       $c0003  year 2300      [$]
3        c0003  year 1900       []
4       &c0004  year 2200      [&]

Python Code Editor:

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Find current directory and file's directory:

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To get the current working directory use

import os
cwd = os.getcwd()

Documentation references for the modules, constants and functions used above:

The os and os.path modules.
The __file__ constant
os.path.realpath(path) (returns "the canonical path of the specified filename, eliminating any symbolic links encountered in the path")
os.path.dirname(path) (returns "the directory name of pathname path")
os.getcwd() (returns "a string representing the current working directory")
os.chdir(path) ("change the current working directory to path")

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