str.split() for splitting in Pandas - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of splitting a pandas Series with default separator

What is the output of the following code snippet?

Pandas

import pandas as pd
s = pd.Series(['apple,banana,orange', 'cat,dog', 'red,blue'])
s_split = s.str.split()
print(s_split)

A

0    [apple, banana, orange]
1           [cat, dog]
2           [red, blue]
dtype: object

B

tcejbo :epytd
]eulb ,der[           2
]god ,tac[           1
]egnaro ,ananab ,elppa[    0

C

tcejbo :epytd
]eulb,der[           2
]god,tac[           1
]egnaro,ananab,elppa[    0

D

0    [apple,banana,orange]
1           [cat,dog]
2           [red,blue]
dtype: object

💡 Hint

Remember that str.split() without arguments splits on whitespace by default.

The str.split() method without arguments splits on whitespace. Since the strings have no spaces, the entire string remains as one element in the list.

❓ data_output

intermediate

Splitting a pandas Series with a comma separator

What is the output of splitting the Series by comma using str.split(",")?

Pandas

import pandas as pd
s = pd.Series(['apple,banana,orange', 'cat,dog', 'red,blue'])
s_split = s.str.split(",")
print(s_split)

A

0    [apple, banana, orange]
1           [cat, dog]
2           [red, blue]
dtype: object

B

0    [apple,banana,orange]
1           [cat,dog]
2           [red,blue]
dtype: object

C

0    [apple banana orange]
1           [cat dog]
2           [red blue]
dtype: object

D

0    apple
1    banana
2    orange
dtype: object

💡 Hint

Use the comma as the separator to split the strings.

Using str.split(",") splits each string at commas, producing lists of words without commas and with spaces removed.

❓ visualization

advanced

Visualizing split results with expand=True

What is the DataFrame output when splitting the Series with expand=True?

Pandas

import pandas as pd
s = pd.Series(['apple,banana,orange', 'cat,dog', 'red,blue'])
s_split_df = s.str.split(",", expand=True)
print(s_split_df)

A

0    apple
1    banana
2    orange
dtype: object

B

        0       1       2
0   apple  banana  orange
1     cat     dog    None
2     red    blue    None

C

0    [apple, banana, orange]
1           [cat, dog]
2           [red, blue]
dtype: object

D

        0       1       2
0   apple  banana  orange
1     cat     dog     dog
2     red    blue    blue

💡 Hint

expand=True returns a DataFrame with each split part in its own column.

The expand=True option splits the strings into separate columns. Missing values are filled with None (NaN).

🔧 Debug

advanced

Identify the error in using str.split with regex separator

What error does the following code raise?

Pandas

import pandas as pd
s = pd.Series(['apple1banana2orange', 'cat3dog', 'red4blue'])
s_split = s.str.split(r'\d')
print(s_split)

A No error, output is lists split at digits

B TypeError: unhashable type: 'list'

C ValueError: regex pattern error

D AttributeError: 'Series' object has no attribute 'str'

💡 Hint

Check if str.split supports regex patterns by default.

str.split in pandas supports regex patterns by default, so splitting on digits works without error.

🚀 Application

expert

Extracting first word from a pandas Series using str.split

Given a Series of sentences, which code correctly extracts the first word of each sentence?

Pandas

import pandas as pd
s = pd.Series(['Data science is fun', 'Python is great', 'Split strings easily'])

A s.str.split().str[-1]

B s.str.split(',').str[0]

C s.str.split().str[0]

D s.str.split(' ')[1]

💡 Hint

Use str.split() to split by whitespace and select the first element.

str.split() splits by whitespace by default. Using str[0] selects the first word from each list.