from pylab import *


class particle(object):

    def __init__(self,mass,charge,spin,pos):
        self.move(pos)
        self.set_mass(mass)

    def set_mass(self,mass):
        self.mass = mass

    def move(self,pos):
        self.position = pos

    def __str__(self):
        report = 'Particle has following properties:\n'
        report += 'mass: {}'.format(self.mass)
        return report

def fun(a,b):
    print "Hi, the sum of {} + {} is {}".format(a,b,a+b)

def main():
    print "hello today's world"
    fun(1,1)
    p = particle(1.,1.,0.5,[0.,0.,0.])
    print p

    x,y = loadtxt('data.dat',unpack=True)
    m = (x>3)*(x<9)
    fig,ax = subplots()
    ax.set_xlabel('X',fontsize=14)
    ax.set_ylabel('Y',fontsize=14)
    ax.plot(x[m],y[m],'ro',markersize=5)
    ax.plot(x,y,'ko',markersize=2)
    ax.set_xlim([0,15])
    ax.set_ylim([0,15])
    savefig('demo.pdf')
    show()

if __name__ == "__main__":
    main()