试图从一个.txt文件

Question

我试图找出如何计算使用在一个文本文件中的坐标的线段的长度计算点之间的距离：

X,Y format (x,y,x,y,x,y,etc...)

4.5,10.0,4.5,5.7,5.5,2.5,6.5,0.3,6.8,0.0,1.0,1.0,3.5,3.5,2,5,6.0,2.0

这是我到目前为止：

Python

# -*- coding: cp1252 -*- 
#Starter code for GIS301 Lab 2 
#GIS301Lab2Starter.py 

import math 

#----------------------------------------------------------- 
#Procedure for reading a coordinate text file 
#in x1,y1,x2,y2,… xn,yn format 
#and resulting in a list as type float 

#open file to read 
file = open(r'C:\Users\Tristan\Desktop\USB_Backup_10-4-16\2016-2017\Fall2016\SpatialDataStructures\Labs\Lab2\points.txt','r') 

#read file to string 
coordString = file.read() 
#Split coordString into list elements 
coordList = coordString.split(',') 
#convert from string to float type 
for index, item in enumerate(coordList): 
    coordList[index] = float(coordList[index]) 
file.close 
#----------------------------------------------------------- 
print (coordList)  
#add more code here 
numPoints = len(coordList)/2 
print("Number of Points") 
print (numPoints) 


x = [float(r) for r in coordList[0::2]] 
y = [float(r) for r in coordList[1::2]] 

xy = list(zip(x,y)) 


# pre-define distance and add subsequent distances 
dist = 0 
for r in coordList(len(xy)-1): 
    dist += ((xy[r][0]-xy[r+1][0])**2 + (xy[r][1]-xy[r+1][1])**2)**0.5 

print (dist) 



#for r in coordList(len(xy)-1): 
# dist += ((xy[r][0]-xy[r+1][0])**2 + (xy[r][1]-xy[r+1][1])**2)**0.5 

When I run it in PyhthonWin:

Traceback (most recent call last): 
    File "C:\Users\Tristan\Desktop\USB_Backup_10-4-16\2016-2017\Fall2016\SpatialDataStructures\Labs\Lab2\GOERSLab2.py", line 39, in <module> 
    for r in coordList(len(xy)-1): 
TypeError: 'list' object is not callable 

的方程n用于计算两点之间的距离为： http://i.stack.imgur.com/vOcu0.png

然后我需要将它们全部加起来！

Answer 1

从你所提供的，我没有看到需要过度复杂这一点。假设你可以正确导入文本文件数据，并拆分它，你可以这样做：

points = ['4.5','10.0','4.5','5.7','5.5','2.5','6.5','0.3','6.8','0.0','1.0','1.0','3.5','3.5','2','5','6.0','2.0'] 


x = [float(r) for r in points[0::2]] 
y = [float(r) for r in points[1::2]] 

# put x/y coordinates in tuples 
xy = list(zip(x,y)) 

# pre-define distance and add subsequent distances 
dist = 0 
for r in xrange(len(xy)-1): 
    dist += ((xy[r][0]-xy[r+1][0])**2 + (xy[r][1]-xy[r+1][1])**2)**0.5 

我觉得东西沿着这些路线将工作做好（你甚至不需要把坐标元组，真）。这是否符合你所需要的？