串浮動錯誤

Question

我想比較這兩個名單：使用此方法

hexvalonsides = ['0.0', '0.3968708', '0.4124191', '0.5403639', '0.6150017', '0.8629506', '0.5946117', '0.4553542', '0.506171', '0.5026515', '0.0'] 
hexvalonsides = ['0.2505809', '0.247734', '0.0', '0.169306', '0.06264286', '0.3082903', '0.4218272', '0.4553542', '0.506171', '0.5026515', '0.0'] 

：

for i in range(0, len(hexvalonsides)): 
    for value in newhexvalonsides: 
     if float(hexvalonsides[i]) - 0.5 <= value <= float(hexvalonsides[i]) + 0.05: 
      count += 1 

不過，我不斷收到一個錯誤ValueError: could not convert string to float: .我想這是因爲在原始文件，我提取了列表，我手動輸入了缺失數據的0.0值。不過，我不確定我在這裏如何解決這個問題。我應該輸入不同的0.0嗎？有任何想法嗎？

Answer 1

新的答案：

檢查您輸入的數據。

只有這樣，你可以得到以下錯誤消息：

ValueError: could not convert string to float: .

是當你有形式.

如String：

print float('.') 

輸出：

ValueError: could not convert string to float: . 

OLD答：

這是工作在我身邊：

hexvalonsides = ['0.0', '0.3968708', '0.4124191', '0.5403639', '0.6150017', '0.8629506', '0.5946117', '0.4553542', '0.506171', '0.5026515', '0.0'] 
newhexvalonsides = ['0.2505809', '0.247734', '0.0', '0.169306', '0.06264286', '0.3082903', '0.4218272', '0.4553542', '0.506171', '0.5026515', '0.0'] 

tmp = zip([ float(x) for x in hexvalonsides], 
      [ float(x) for x in newhexvalonsides]) 

count = sum(1 if x[0]-0.5 <= x[1] <= x[0]+0.05 else 0 for x in tmp) 

print count 

Answer 2

你需要轉換value的浮動，以及：

for i in range(0, len(hexvalonsides)): 
    for value in newhexvalonsides: 
     if float(hexvalonsides[i]) - 0.5 <= float(value) <= float(hexvalonsides[i]) + 0.05: 
      count += 1 

雖然你可以做到這一點更優雅地使用map：

import operator 

diff=map(operator.sub,map(float,hexvalonsides),map(float,newhexvalonsides)) 

print len(filter(lambda x:x>-0.5 and x<0.05,diff))