Pandas DataFrame ‘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 –
- See the documentation for eval() for complete details on the keyword arguments accepted by query().

Returns:

ndarray, scalar, pandas object, or None – The result of the evaluation or None if inplace=True

df = pd.DataFrame({'A': range(1, 6), 'B': range(10, 0, -2)})
df

df.eval('A + B')

0    11
1    10
2     9
3     8
4     7
dtype: int64

df.eval('C = A + B')

df.eval('C = A + B', inplace=True)
df