import math
L1=['104','32','249','177']
L2=['191','538','317','795']
L3=['735','346','542','429']
L4=['434','277','659','132']
L5=['866','569','46','763']
def Search_data(store_pdb,List_data):
    f_pdb=open(store_pdb,'r')
    lines=f_pdb.readlines()
    f_pdb.close()
    space_coordinate_1=[]
    space_coordinate_2=[]
    for line in lines:
        line_data=line.split()
        if List_data[0] in line_data[4:] and 'P' in line_data[2:]:
            space_coordinate_1.append(line_data[-5:-2])
            continue
        elif List_data[1] in line_data[4:] and 'P' in line_data[2:]:
            space_coordinate_1.append(line_data[-5:-2])
            continue
        elif List_data[2] in line_data[4:] and 'P' in line_data[2:]:
            space_coordinate_2.append(line_data[-5:-2])
            continue
        elif List_data[3] in line_data[4:] and 'P' in line_data[2:]:
            space_coordinate_2.append(line_data[-5:-2])
            continue
    space_coordinate=(space_coordinate_1,space_coordinate_2)
    return  space_coordinate
def Get_distance(store_pdb,List_data):
    one_tuple_data=Search_data(store_pdb,List_data)
    point_list_one=one_tuple_data[0]
    point_list_two=one_tuple_data[1]
    x1=(float(point_list_one[0][0])+float(point_list_one[1][0]))/2
    y1=(float(point_list_one[0][1])+float(point_list_one[1][1]))/2
    z1=(float(point_list_one[0][2])+float(point_list_one[1][2]))/2
    x2=(float(point_list_two[0][0])+float(point_list_two[1][0]))/2
    y2=(float(point_list_two[0][1])+float(point_list_two[1][1]))/2
    z2=(float(point_list_two[0][2])+float(point_list_two[1][2]))/2
    d=math.sqrt((x1-x2)**2+(y1-y2)**2+(z1-z2)**2)-20
    return d
def distance_files(store_pdb):
    L=[L1,L2,L3,L4,L5]
    for i in range(0,len(L)):
        distance_file=open('distance files %d'%(i+1),'a+')
        d=Get_distance(store_pdb,L[i])
        distance_file.write(str(d)+'\n')
        distance_file.close()
if __name__=="__main__":

    distance_files('1.pdb')

其中列表L为源文件中要找的第几行的数据，每一行中都有空间的一个点的坐标，srore_pdb为存放数据的pdb文件，list_data为上面的列表