The role of eval function in python

#eval() function is used to execute a string expression and return the value of the expression.

eval function function: Treat the string str as a valid expression to evaluate and return the calculation result. The eval function can realize conversion between list, dict, tuple and str

eval() method syntax:

eval(expression[, globals[, locals]])

Parameters:

• expression -- Expression.

• globals -- Variable scope, global namespace, if provided, must be a dictionary object.

• locals -- Variable scope, local namespace, if provided, can be any mapping object.

Usage examples:

1. Convert string to list

a = "[[1,2], [3,4], [5,6], [7,8], [9,0]]"
print(type(a))
b = eval(a)
print(type(b))
print(b)

2. Convert string to dictionary

a = "{1: 'a', 2: 'b'}"
print(type(a))
b = eval(a)
print(type(b))
print(b)

3. Convert string to tuple

a = "([1,2], [3,4], [5,6], [7,8], (9,0))"
print(type(a))
b=eval(a)
print(type(b))
print(b)

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