ValueError: pattern contains no capture groups - pandas

John D K -

To solve Pandas Error: Valueerror: Pattern Contains No Capture Groups we need to specify a capture group.

Steps to plot 2 variables

  • Import matplotlib library
  • Create DataFrame with correlated data
  • Create the figure and axes object - fig, ax = plt.subplots()
  • Plot the first variable on x and left y axes
  • Plot the second variable on x and secondary y axes

More information can be found: DataFrame.plot - secondary_y

Data

Let's have this DataFrame which will be used to demonstrate the error:

Valueerror: Pattern Contains No Capture Groups

from faker import Faker
import pandas as pd

Faker.seed(0)
fake = Faker()
addr = []
for _ in range(5):
	addr.append(fake.address())
df = pd.DataFrame({'address':addr})
df
address
0 48764 Howard Forge Apt. 421\nVanessaside, VT 79393
1 PSC 4115, Box 7815\nAPO AA 41945
2 778 Brown Plaza\nNorth Jenniferfurt, VT 88077
3 3513 John Divide Suite 115\nRodriguezside, LA 93111
4 398 Wallace Ranch Suite 593\nIvanburgh, AZ 80818

Example

The code below produce the error:

df['address'].str.extract('.+?(?=\n)')

to solve the error we will add parentheses to denote the capture group:

df['address'].str.extract('(.+)?(?=\n)')

So the fix is:

  • '.+?(?=\n)'
  • '(.+)?(?=\n)'

which produce:

0
0 48764 Howard Forge Apt. 421
1 PSC 4115, Box 7815
2 778 Brown Plaza
3 3513 John Divide Suite 115
4 398 Wallace Ranch Suite 593

Output

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