Python DataFrame if-else in one line

Python DataFrame if-else in one line

Here is a response in English only, as per your request:

The if-else statement in Python can be implemented in one line using the .apply() method on a pandas DataFrame. This can be achieved by providing a lambda function that includes an if-else condition. Here's an example:

import pandas as pd
Create a sample DataFrame
data = {'Name': ['Tom', 'Nick', 'John', 'Emma'],
'Age': [20, 21, 19, 22],
'Grade': ['Freshman', 'Sophomore', 'Junior', 'Senior']}
df = pd.DataFrame(data)
Apply an if-else condition to the DataFrame
df['Result'] = df.apply(lambda row: 'Pass' if row['Age'] >= 20 and row['Grade'] != 'Freshman' else 'Fail', axis=1)

In this example, we're applying a lambda function that checks two conditions:

If both conditions are met, the result is 'Pass', otherwise it's 'Fail'. This condition is applied to each row of the DataFrame.

Here's the output:

     Name  Age        Grade    Result
0    Tom   20      Freshman    Fail
1   Nick   21    Sophomore    Pass
2   John   19      Junior    Fail
3   Emma   22       Senior    Pass

As you can see, the if-else condition has been applied to each row of the DataFrame and the resulting 'Pass' or 'Fail' is stored in a new column called Result.

This one-liner approach can be particularly useful when working with large datasets or when you need to perform complex conditions on specific columns.

How to put multiple if statements in one line in Python?

I'll respond in English as per your request.

In Python, you can combine multiple if-else statements into a single line using the and and or logical operators. This technique is commonly referred to as "Chaining If Statements". Here's an example:

x = 10
y = 20
result = (x > 5) and (y < 25) or (x == 10)
print(result)  # Output: True

In this example, the and operator is used to check if both conditions are true (x > 5 and y < 25). If they are, then the expression evaluates to True. However, if either of the conditions is false, the evaluation stops there and returns False.

The or operator is used to provide an alternative condition that will be evaluated if the previous conditions fail. In this case, if x > 5 is true but y < 25 is false (which means y >= 25), then the expression evaluates to True because of the second part of the statement (x == 10).

You can also use parentheses to group the conditions and improve readability. Here's an example:

x = 10
y = 20
result = ((x > 5) and (y < 25)) or (x == 10)
print(result)  # Output: True

This way, you can combine multiple if-else statements into a single line, making your code more concise and easier to read.

When chaining if statements, it's essential to consider the order of operations. Make sure that the logical operators (and and or) are applied correctly to avoid unexpected results. If you're unsure about how Python will evaluate your conditions, try simplifying the expression step by step to better understand the logic.

Remember that while this technique can be useful for concise code, it's still important to prioritize readability and maintainability in your programming.