python - Removing rows from dataframe whose first letter is in lowercase

Python - Removing rows from dataframe whose first letter is in lowercase

To remove rows from a Pandas DataFrame where the first letter of a specific column (e.g., name) is in lowercase, you can use the str accessor combined with boolean indexing. Here's how you can achieve this:

Example DataFrame

import pandas as pd data = { 'name': ['Alice', 'bob', 'Charlie', 'david', 'Edward'], 'age': [25, 30, 35, 40, 45] } df = pd.DataFrame(data) print(df)

This DataFrame looks like this:

 name age 0 Alice 25 1 bob 30 2 Charlie 35 3 david 40 4 Edward 45

Filtering Rows

You can filter out rows where the first letter of the name column is lowercase using the str accessor and the apply method. Here's the code:

# Remove rows where the first letter of 'name' is lowercase df_filtered = df[~df['name'].str[0].str.islower()] print(df_filtered)

This code works as follows:

  1. df['name'].str[0]: Selects the first character of each string in the name column.
  2. .str.islower(): Checks if these characters are lowercase, returning a boolean Series.
  3. ~: Negates the boolean Series, so True becomes False and vice versa.
  4. df[...]: Uses boolean indexing to filter the DataFrame.

Output

The filtered DataFrame will be:

 name age 0 Alice 25 2 Charlie 35 4 Edward 45

Only the rows where the first letter of the name column is uppercase are retained.

Complete Code

Here is the complete code for clarity:

import pandas as pd # Sample data data = { 'name': ['Alice', 'bob', 'Charlie', 'david', 'Edward'], 'age': [25, 30, 35, 40, 45] } # Create DataFrame df = pd.DataFrame(data) print("Original DataFrame:") print(df) # Remove rows where the first letter of 'name' is lowercase df_filtered = df[~df['name'].str[0].str.islower()] print("\nFiltered DataFrame:") print(df_filtered)

This will give you the filtered DataFrame as expected.

Examples

  1. "Remove rows with lowercase first letter pandas"

    Description: Remove rows from a DataFrame where the first letter of a specific column is lowercase.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].str[0].str.isupper()] print(df)

  2. "Pandas filter rows by first letter case"

    Description: Filter rows in a DataFrame by checking if the first letter of a string column is uppercase.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].apply(lambda x: x[0].isupper())] print(df)

  3. "Drop rows with lowercase starting letter in pandas"

    Description: Drop rows in a DataFrame where the starting letter of a column is lowercase.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[~df['name'].str[0].str.islower()] print(df)

  4. "Pandas remove lowercase initial rows"

    Description: Remove DataFrame rows with a lowercase initial letter in a specific column.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].str[0].str.isupper()] print(df)

  5. "Filter pandas DataFrame by first character case"

    Description: Filter a DataFrame by the case of the first character in a string column.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].str[0].apply(str.isupper)] print(df)

  6. "Remove rows with lowercase starting string pandas"

    Description: Remove rows in a DataFrame where the first character of the string column is lowercase.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].map(lambda x: x[0].isupper())] print(df)

  7. "Drop DataFrame rows starting with lowercase letter"

    Description: Drop rows from a DataFrame if a specific column starts with a lowercase letter.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].str[0].map(str.isupper)] print(df)

  8. "Pandas: filter rows by initial letter case"

    Description: Filter rows by the case of the initial letter in a DataFrame column.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].str[0].str.isupper()] print(df)

  9. "Removing rows with lowercase first character in pandas"

    Description: Remove rows from a DataFrame if the first character in a column is lowercase.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[~df['name'].str[0].str.islower()] print(df)

  10. "Filter DataFrame to remove lowercase starting rows"

    Description: Filter a DataFrame to remove rows where a string column starts with a lowercase letter.

    Code:

    import pandas as pd data = {'name': ['alice', 'Bob', 'charlie', 'David']} df = pd.DataFrame(data) df = df[df['name'].apply(lambda x: x[0].isupper())] print(df)

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