Minus state $\lvert -\rangle$ implementation using Qiskit. The $\lvert -\rangle$ state is prepared by applying an X gate followed by a Hadamard gate to $\lvert 0\rangle$.

from qiskit import QuantumCircuit
from qiskit.quantum_info import Statevector
 
qc = QuantumCircuit(1)
qc.x(0)  # |0> -> |1>
qc.h(0)  # |1> -> |-> = (|0> - |1>) / sqrt(2)
print(Statevector(qc))
# Statevector([ 0.70710678+0.j, -0.70710678+0.j], dims=(2,))