为什么在给定文本行中的数字时 IsNumeric() 返回 False

Question

我正在编写一些 python 代码来评估文件的每一行，如果该行是一个数字，它应该返回 false 并忽略该行。此代码来自https://github.com/geoff604/sbv2txt/blob/master/README.md，我正在努力修改它。

但是，无论哪一行被传递给 IsNumeric() 函数，它的计算结果仍然为 False。我将相同的数字硬编码为字符串"2"，并将其正确评估为True。

在评估文本行时我是否遗漏了什么？

import sys

def isCaptionText(lineIndex):
    if lineIndex.isnumeric():
        print('True')
        return False
    else:
        return lineIndex

if len(sys.argv) < 3:
    print('Arguments: [source sbv filename] [destination txt filename]')
    sys.exit()

with open(sys.argv[1]) as f1:
    with open(sys.argv[2], 'a') as f2:
        lines = f1.readlines()
        for index, line in enumerate(lines):
            if isCaptionText(line):
                f2.write(line)

print('Output complete. File written as ' + sys.argv[2])

我正在分析的文件是我将在下面以缩写形式列出的文本。

2
00:00:04,360 --> 00:00:08,861
St. Louis' home for arts,
education and culture.

3
00:00:08,861 --> 00:00:11,444
(upbeat music)

4
00:00:12,290 --> 00:00:13,610
- [Woman] But we're in a global pandemic.

5
00:00:13,610 --> 00:00:16,000
We're also in a global blood shortage.

6
00:00:16,000 --> 00:00:18,230
- [Man] The more I dug,
the more it took me back

Answer 1

因此，每当您有新行时，python 都会看到文本和新行。例如：如果该行是1，f1.readlines() 将其视为1\n，因此isNumeric 将返回false。这里的技巧是使用strip

for index, line in enumerate(Lines):
if isCaptionText(line.strip()):
   print(line)

Answer 2

• 因为文件中的每一行都有一个换行符，这取决于你使用的操作系统，比如第一行2，在Windows中实际上是2\n。
• 如果您想在特定操作系统上运行代码，可以使用replace 或strip 来获取换行符。

Windows 上的示例固定代码：

with open("input.txt") as f1:
    lines = f1.readlines()
    for index, line in enumerate(lines):
        print(line.replace("\n","").isnumeric())

input.txt

2
00:00:04,360 --> 00:00:08,861
St. Louis' home for arts,
education and culture.

3
00:00:08,861 --> 00:00:11,444
(upbeat music)

4
00:00:12,290 --> 00:00:13,610
- [Woman] But we're in a global pandemic.

5
00:00:13,610 --> 00:00:16,000
We're also in a global blood shortage.

6
00:00:16,000 --> 00:00:18,230
- [Man] The more I dug,
the more it took me back

结果：

True
False
False
False
False
True
False
False
False
True
False
False
False
True
False
False
False
True
False
False
False

Answer 3

使用 try 和 except 块

try:
    int(lineIndex)
    print('True')
    return True
except ValueError:
    return False

或使用type()

if type(lineIndex) == int:
    print('True')
    return False
else:
    return lineIndex

如果您有小数，请检查 float