Python 2.7将2d字符串数组转换为浮点数组

Question

我在.txt文件中读取以下字符串

{{1,2,3,0}，{4,5,6,7}，{8， -1,9,0}}

使用lin = lin.strip()以除去 '\ N'

然后我代替{和}至[和]使用

lin = lin.replace ("{", "[") 

lin = lin.replace ("}", "]") 

我的目标是林转换成浮动2d数组。所以，我没有

my_matrix = np.array(lin, dtype=float) 

，但我得到一个错误信息：“ValueError异常：无法将字符串转换为float：[1,2,3,0]，[1,1,1,2]，[0 ，-1,3,9]]“

删除dtype，我得到一个字符串数组。我已经尝试将lin乘以1.0，使用.astype（float）创建lin的副本，但似乎没有任何工作。

Answer 1

我使用JSON库来解析文件的内容，然后遍历数组并将每个元素转换为float。然而，一个整数解决方案可能已经足够你想要的。那个更快更短。

import json 

fc = '{{1,2,3,0},{4,5,6,7},{8,-1,9,0}}' 

a = json.loads(fc.replace('{','[').replace('}',']')) 

print(a) # a is now array of integers. this might be enough 

for linenumber, linecontent in enumerate(a): 
    for elementnumber, element in enumerate(linecontent): 
     a[linenumber][elementnumber] = float(element) 

print(a) # a is now array of floats 

较短的解决方案

import json 

fc = '{{1,2,3,0},{4,5,6,7},{8,-1,9,0}}' 

a = json.loads(fc.replace('{','[').replace('}',']')) 

print(a) # a is now array of integers. this might be enough 

a = [[float(c) for c in b] for b in a] 

print(a) # a is now array of floats 

（同时适用于Python 2和3）

Answer 2

import numpy as np 

readStr = "{{1,2,3,0},{4,5,6,7},{8,-1,9,0}}" 
readStr = readStr[2:-2] 
# Originally read string is now -> "1,2,3,0},{4,5,6,7},{8,-1,9,0" 

line = readStr.split("},{") 
# line is now a list object -> ["1,2,3,0", "4,5,6,7", "8,-1,9,0"] 

array = [] 
temp = [] 
# Now we iterate through 'line', convert each element into a list, and 
#  then append said list to 'array' on each iteration of 'line' 
for string in line: 
    num_array = string.split(',') 
    for num in num_array: 
     temp.append(num) 
    array.append(temp) 
    temp = [] 

# Now with 'array' -> [[1,2,3,0], [4,5,6,7], [8,-1,9,0]] 
my_matrix = np.array(array, dtype = float) 

# my_matrix = [[1.0, 2.0, 3.0, 0.0] 
#    [4.0, 5.0, 6.0, 7.0] 
#    [8.0, -1.0, 9.0, 0.0]] 

虽然这可能不是最完美的解决方案，我认为这是容易跟踪和给你准确的你在找什么。