Python Pandas – Find the maximum value of a column and return its corresponding row values

To find the maximum value of a column and return its corresponding row values in Pandas, we can use df.loc[df[col].idxmax()]. This method first finds the index of the maximum value using idxmax(), then uses loc[] to retrieve the entire row.

Syntax

df.loc[df[column_name].idxmax()]

Where:

• df − The DataFrame
• column_name − The column to find the maximum value in
• idxmax() − Returns the index of the maximum value
• loc[] − Selects the row by index

Example

Let's create a DataFrame and find the maximum values for different columns ?

import pandas as pd

# Create a DataFrame
df = pd.DataFrame(
    {
        "x": [5, 2, 7, 0],
        "y": [4, 7, 5, 1],
        "z": [9, 3, 5, 1]
    }
)
print("Input DataFrame:")
print(df)

Input DataFrame:
   x  y  z
0  5  4  9
1  2  7  3
2  7  5  5
3  0  1  1

Finding Maximum in Column 'x'

import pandas as pd

df = pd.DataFrame(
    {
        "x": [5, 2, 7, 0],
        "y": [4, 7, 5, 1],
        "z": [9, 3, 5, 1]
    }
)

col = "x"
max_row = df.loc[df[col].idxmax()]
print("Maximum value of column", col, "and its corresponding row values:")
print(max_row)

Maximum value of column x and its corresponding row values:
x    7
y    5
z    5
Name: 2, dtype: int64

Finding Maximum in Multiple Columns

import pandas as pd

df = pd.DataFrame(
    {
        "x": [5, 2, 7, 0],
        "y": [4, 7, 5, 1],
        "z": [9, 3, 5, 1]
    }
)

# Check maximum for all columns
for col in ["x", "y", "z"]:
    max_row = df.loc[df[col].idxmax()]
    print(f"Column '{col}' maximum (value={max_row[col]}) at index {df[col].idxmax()}:")
    print(max_row)
    print()

Column 'x' maximum (value=7) at index 2:
x    7
y    5
z    5
Name: 2, dtype: int64

Column 'y' maximum (value=7) at index 1:
x    2
y    7
z    3
Name: 1, dtype: int64

Column 'z' maximum (value=9) at index 0:
x    5
y    4
z    9
Name: 0, dtype: int64

Alternative Methods

Conclusion

Use df.loc[df[col].idxmax()] to find the maximum value in a column and retrieve the complete corresponding row. This method combines idxmax() to find the index and loc[] to access the full row data efficiently.