Pandas DataFrame ‘eval’ Method.
Table Of Contents:
- Syntax Of ‘eval( )’ Method In Pandas.
- Examples ‘eval( )’ Method.
(1) Syntax:
DataFrame.eval(expr, *, inplace=False, **kwargs)
Description:
- Evaluate a string describing operations on DataFrame columns.
- Operates on columns only, not specific rows or elements.
- This allows eval to run arbitrary code, which can make you vulnerable to code injection if you pass user input to this function.
Parameters:
- expr: str –
- The expression string to evaluate.
- in place: bool, default False –
- If the expression contains an assignment, whether to perform the operation in place and mutate the existing DataFrame. Otherwise, a new DataFrame is returned.
- **kwargs –
Returns:
- ndarray, scalar, pandas object, or None – The result of the evaluation or None if
inplace=True
(2) Examples Of ‘eval()’ Method:
Example-1
df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
df
Output:
# Adding Column ‘A’ and ‘B’.
df.eval('A + B')
Output:
0 11
1 10
2 9
3 8
4 7
dtype: int64
# Creating A New Column Using ‘eval’.
df.eval('C = A + B')
Output:
# Modifying The Original DataFrame.
df.eval('C = A + B', inplace=True)
df