[Python] Extract only numbers from lists and character strings

I am a beginner of scraping who has just started scraping with Python. This time, make a note of how to extract only the numbers from the data extracted by scraping.

Purpose

Extract only numbers from the data extracted by scraping

Implementation

Extract only numbers using ** regular expressions **

Use the re module. Execute the following command from the terminal to install regex.

$ pip install regex

Next, let's import the ** re module ** into sample.py.

`sample.py`


import re

Now you are ready to use the re module.

Extract only numbers from strings

`sample.py`


import re

dt = "regnkrnfskrngkaer gksgnkq laergnnktga3r erfkl 400 registrants aelrkna erglknnarg"
num = re.sub("\\D", "", dt)
print(num)

# 400

Extract only numbers from the list

`sample.py`


import re

dt = ['regnkrnfskrngkaer', 'gksgnkq', 'laergnnktgar', 'erfkl', '400 registrants', 'aelrkna erglknnarg']
dt_str = ",".join(dt)
dt_num = re.sub("\\D", "", dt_str)
print(dt_num)

# 400

Extract only specific numbers from a list of mixed strings and numbers

Failure example

`sample.py`


import re

dt = ['regr111kaer', 'gg443nkq', 'laen56nktgar', 'er39fkl', '400 registrants', 'ael09narg']
dt_str = ",".join(dt)
dt_num = re.sub("\\D", "", dt_str)
print(dt_num)

# 111443563940009

Success story

`sample.py`


import re

dt = ['regr111kaer', 'gg443nkq', 'laen56nktgar', 'er39fkl', '400 registrants', 'ael09narg']
dt_pop = (dt.pop(4))
dt_num = re.sub("\\D", "", dt_pop)
print(dt_num)

# 400

reference https://qiita.com/sakamossan/items/161db7418ade037f6f3d https://qiita.com/ikanamazu/items/ba2a32a1a5924f3bd8e9

Recommended Posts

[Python] Extract only numbers from lists and character strings

3-3, Python strings and character codes

[Beginner] Extract character strings with Python

Extract strings from files in Python

# 5 [python3] Extract characters from a character string

Links and memos of Python character code strings

Extract "current date only" and "current date and time" with python datetime.

[Python beginner] Extract prefectures and cities from addresses (3 lines).

Manipulating Python character lists (arrays)

Extract only Python for preprocessing