Python 文件解析器 - 以 10 为底的 int() 的无效文字：''

Question

我正在尝试解析这种格式的文件

2010-11-04 00:03:50.209589 M003 ON Sleeping begin
2010-11-04 00:03:57.399391 M003 OFF
2010-11-04 00:15:08.984841 T002 21.5
2010-11-04 00:30:19.185547 T003 21
2010-11-04 00:30:19.385336 T004 21

我需要 select 第三列中的数字。在 select 该行之后，我 select 它的第三个字段。然后我拆分它，select 类型（M 或 T）和数字（第三个字段的其余部分）。这里的问题是：当我尝试 select 数字时，出现以下错误：Invalid literal for int() with base 10: ''.我已经尝试了很多方法（如删除 EOF 或任何类型的结束字符）到“num”，但我仍然遇到这个问题。

temp_sensors = 0 #total number of temperature sensors
f = open('data', 'r')#open the dataset
line = f.readline() #reading line

while line:
    step = line.split()#dividing the line into different words
    sensor_type = step[2][:1]
    sensor_number = step[2][2:]
    sensor_value = step[3]
    #print(sensor_number)
    #num = sensor_number[:2]
    #print(type(num))
    num = sensor_number.rstrip()
    appoggio = int(num)
    #print(type(num))
    if sensor_type == "T":
        if appoggio > temp_sensors:
            temp_sensors = appoggio
    line = f.readline()
print("NUMERO TEMP MAX: "+ str (temp_sensors))

要运行代码，您需要一个包含多个传感器事件的 txt 文件 data.txt，格式如前所示。我得到的错误是：

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
<ipython-input-6-b89fbf305c4a> in <module>
 28 #   print(type(num))
 29     num = sensor_number.rstrip()
---> 30     appoggio = int(num)
 31     #print(type(appoggio))
 32     #print(type(num)) 

ValueError: invalid literal for int() with base 10: ''

Answer 1

我同意前面几位发言者的看法，一行似乎使用了不同的格式。因此，空字符串在转换为整数时似乎会引发错误。我的建议是提前测试格式。

import re

def readdata(fname):
    ptrn = r'^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}.\d{6} [MT]\d{3} .*\s+$'
    sensor_count = 0
    with open(fname) as fp:
        for i,line in enumerate(fp):
            if not re.match(ptrn, line):
                print(f'Illegal format in line {i}: {line!r}')
                continue

            dt,tm,sensor,value = line.rstrip().split(' ',3)
            sensor_type,sensor_number = sensor[0],int(sensor[1:])
            print(sensor_type, sensor_number)
            if sensor_type == 'T':
                sensor_count = max(sensor_count, sensor_number)
    print(f'Number of temperature sensors: {sensor_count}')

Python 文件解析器 - 以 10 为底的 int() 的无效文字：''

Python file parser - invalid literal for int() with base 10: ''

python

string

parsing

integer

type-conversion