如何在Python中将分割字符串转换为浮点数但忽略对象？

Question

我有一个文本文件 'lines.txt'，内容如下：

0.02 7 433 649 239 32
0.04 84 43 594 2 321
0.06 65 34 94 5 138 
0.08 43 56 23 10 432
1.00 2 382 37 29 102
1.20 573 475 82 757 29
Time (s)
Number (unit)
Third (none) 
Fourth (none)
Fifth (none)
Test (none)

底部的字符串其实是上面数据的列名（从左到右，比如 Time_1 是 0.02，Number_1 是 7 等等）。我已经用 .split 函数把每一行的字符串分开了。现在我想把底部的6个文本字符串作为列头，给现在分开的浮点数字符串加上列名。

我该怎么写一个函数，把这两部分数据分开，这样我就可以把底部的字符串当作列名来用？

到目前为止，我有：

f = open('lines.txt','r')
lines = f.readlines()

for line in lines:
    data = line.split()
    data1 = line.strip()
    print(data)


for line in data:
    if data is not object:
        data = [float(x) for x in data] 

我觉得这段代码可以把数字形式的数据转换成浮点数，但我无法让它在遇到文本字符串（比如 Time (s)）时停止读取。任何帮助都很感激。

Answer 1

希望你需要一个数组，第一行是标题，后面的行是数据。

f = open('try.txt','r')
lines = f.readlines()
data={}
cols=[]

# checking each lines and converting all the data to float which is not colomun heading
for index,line in enumerate(lines):
    data[index]=[]
    for col in line.split():
      try:
        data[index].append(float(col))
      except ValueError:
         #if data is not convertable to float add the main line data to cols array
         cols.append(line)
         
         break
finalarray = []
for key,value in data.items():
   if len(value)==0:
      #ignoring the empty dict which represents line for col
      continue
   else:
      #appending lists of float to final array
      finalarray.append(value)
#inserting col headings to the index zero
finalarray.insert(0,cols)
#printing final array where line one is col heading and all other lines is rowdata
print(finalarray)

Answer 2

如果你知道最后的6行总是你的列名，那么你可以把这个列表分成两部分。

f = open('lines.txt','r')
lines = f.readlines()
columns = lines[-6:]
lines = lines[:-6]
for line in lines:
    data = line.split()
    data1 = line.strip()
    print(data)...

使用 columns 来给你的列命名。

Answer 3

如果你无法转换这行内容，可以把它保存为标题：

with open('lines.txt') as file:
    data = []
    headings = []
    for line in file:
        try:
            data.append([float(x) for x in line.split()])
        except ValueError:
            headings.append(line.strip())
print(headings)
for line in data:
    print(line)

输出结果：

['Time (s)', 'Number (unit)', 'Third (none)', 'Fourth (none)', 'Fifth (none)', 'Test (none)']
[0.02, 7.0, 433.0, 649.0, 239.0, 32.0]
[0.04, 84.0, 43.0, 594.0, 2.0, 321.0]
[0.06, 65.0, 34.0, 94.0, 5.0, 138.0]
[0.08, 43.0, 56.0, 23.0, 10.0, 432.0]
[1.0, 2.0, 382.0, 37.0, 29.0, 102.0]
[1.2, 573.0, 475.0, 82.0, 757.0, 29.0]

要写入一个CSV文件，可以添加：

with open('output.csv', 'w', newline='') as file:
    writer = csv.writer(file)
    writer.writerow(headings)
    writer.writerows(data)

output.csv：

Time (s),Number (unit),Third (none),Fourth (none),Fifth (none),Test (none)
0.02,7.0,433.0,649.0,239.0,32.0
0.04,84.0,43.0,594.0,2.0,321.0
0.06,65.0,34.0,94.0,5.0,138.0
0.08,43.0,56.0,23.0,10.0,432.0
1.0,2.0,382.0,37.0,29.0,102.0
1.2,573.0,475.0,82.0,757.0,29.0