在Python或NumPy中已经有一些方法可以确定数字的格式吗？

huangapple
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英文:

Is there already something in python or numpy to determine a number's format?

问题

  1. 我需要确定一个字符串是一个普通整数，一个普通浮点数，一个使用 `e` 的浮点数，或者无法解析为数字。这是我想出的方法，但这感觉像是已经存在的东西，也许在numpy中？我对库和谷歌进行了简要的扫描，没有看到任何东西，这已经是一个事情了吗，只是我没有看到吗？
  3. PLAIN_INT, PLAIN_FLOAT, E_FLOAT, STRING = range(4)
  5. # 应该只是可选的 - 然后是数字
  6. sample_plain_ints = ['1', '0', '-5', '333333333']
  7. # 需要包含一个点
  8. plain_floats = ['1.0', '-5.0', '-33.212', '0.0', '-1.', '-3.']
  9. # 不需要包含一个点
  10. e_floats = ['1.3e5', '-1.2e5', '0.0e0', '5e-3', '3e23', '3E5', '-3E-12']
  11. # 其他
  12. strings = ['aether', '1ee3', 'buzz', 'eeep', '121212beep']
  14. def determine_str_type(item):
  15.     try:
  16.         float(item)
  17.         try:
  18.             int(item)
  19.             return PLAIN_INT
  20.         except ValueError:
  21.             return E_FLOAT if 'E' in item.upper() else PLAIN_FLOAT
  22.     except ValueError:
  23.         return STRING
  25. assert all([determine_str_type(item) == PLAIN_INT for item in sample_plain_ints])
  26. assert all([determine_str_type(item) == PLAIN_FLOAT for item in plain_floats])
  27. assert all([determine_str_type(item) == E_FLOAT for item in e_floats])
  28. assert all([determine_str_type(item) == STRING for item in strings])
英文:

I need to determine if a string is a plain int, a plain float, a float using e, or not parsable as a number. Here's what I came up with, but this feels like something that probably already exists, perhaps in numpy? I did a brief scan of the libraries and google and didn't see anything, is this already a thing and I'm just not seeing it?

  1. PLAIN_INT, PLAIN_FLOAT, E_FLOAT, STRING = range(4)
  3. # should be just optionally - then numbers
  4. sample_plain_ints = ['1', '0', '-5', '333333333']
  5. # need to contain a dot
  6. plain_floats = ['1.0', '-5.0', '-33.212', '0.0', '-1.', '-3.']
  7. # do not need to contain a dot
  8. e_floats = ['1.3e5', '-1.2e5', '0.0e0', '5e-3', '3e23', '3E5', '-3E-12']
  9. # other
  10. strings = ['aether', '1ee3', 'buzz', 'eeep', '121212beep']
  13. def determine_str_type(item):
  14.     try:
  15.         float(item)
  16.         try:
  17.             int(item)
  18.             return PLAIN_INT
  19.         except ValueError:
  20.             return E_FLOAT if 'E' in item.upper() else PLAIN_FLOAT
  21.     except ValueError:
  22.         return STRING
  25. assert all([determine_str_type(item) == PLAIN_INT for item in sample_plain_ints])
  26. assert all([determine_str_type(item) == PLAIN_FLOAT for item in plain_floats])
  27. assert all([determine_str_type(item) == E_FLOAT for item in e_floats])
  28. assert all([determine_str_type(item) == STRING for item in strings])

答案1

得分: 5

  1. 我会用正则表达式 (`(-?\d+)(\.\d*)?([eE]-?\d+)?$`) 来处理，捕获不同的部分，然后根据输出决定：
  3. ```python
  4. import re
  6. lst = ['1', '0', '-5', '333333333', '1.0', '-5.0', '-33.212', '0.0', '-1.', '-3.', '1.3e5', '-1.2e5', '0.0e0', '5e-3', '3e23', '3E5', '-3E-12', 'aether', '1ee3', 'buzz', 'eeep', '121212beep']
  8. def determine_str_type(s):
  9.     pat = re.compile(r'(-?\d+)(\.\d*)?([eE]-?\d+)?$')
  10.     match m.groups() if (m:=pat.match(s)) else None:
  11.         case None:
  12.             return 'STRING '
  13.         case (_, None, None):
  14.             return 'PLAIN_INT'
  15.         case (_, _, None):
  16.             return 'PLAIN_FLOAT'
  17.         case (_, _, _):
  18.             return 'E_FLOAT'
  19.         
  20. for s in lst:
  21.     print(f'{s: <11}: {determine_str_type(s)}')

输出：

  1. 1          : PLAIN_INT
  2. 0          : PLAIN_INT
  3. -5         : PLAIN_INT
  4. 333333333  : PLAIN_INT
  5. 1.0        : PLAIN_FLOAT
  6. -5.0       : PLAIN_FLOAT
  7. -33.212    : PLAIN_FLOAT
  8. 0.0        : PLAIN_FLOAT
  9. -1.        : PLAIN_FLOAT
  10. -3.        : PLAIN_FLOAT
  11. 1.3e5      : E_FLOAT
  12. -1.2e5     : E_FLOAT
  13. 0.0e0      : E_FLOAT
  14. 5e-3       : E_FLOAT
  15. 3e23       : E_FLOAT
  16. 3E5        : E_FLOAT
  17. -3E-12     : E_FLOAT
  18. aether     : STRING 
  19. 1ee3       : STRING 
  20. buzz       : STRING 
  21. eeep       : STRING 
  22. 121212beep : STRING

正则表达式演示

  2. <details>
  3. <summary>英文:</summary>
  5. I would use a regex for that (`(-?\d+)(\.\d*)?([eE]-?\d+)?$`), capture the different parts and decide depending on the output:

import re

lst = ['1', '0', '-5', '333333333', '1.0', '-5.0', '-33.212', '0.0', '-1.', '-3.', '1.3e5', '-1.2e5', '0.0e0', '5e-3', '3e23', '3E5', '-3E-12', 'aether', '1ee3', 'buzz', 'eeep', '121212beep']

def determine_str_type(s):
pat = re.compile(r'(-?\d+)(.\d*)?([eE]-?\d+)?$')
match m.groups() if (m:=pat.match(s)) else None:
case None:
return 'STRING '
case (, None, None):
return 'PLAIN_INT'
case (, , None):
return 'PLAIN_FLOAT'
case (, _, _):
return 'E_FLOAT'

for s in lst:
print(f'{s: <11}: {determine_str_type(s)}')

  1. Output:

1 : PLAIN_INT
0 : PLAIN_INT
-5 : PLAIN_INT
333333333 : PLAIN_INT
1.0 : PLAIN_FLOAT
-5.0 : PLAIN_FLOAT
-33.212 : PLAIN_FLOAT
0.0 : PLAIN_FLOAT
-1. : PLAIN_FLOAT
-3. : PLAIN_FLOAT
1.3e5 : E_FLOAT
-1.2e5 : E_FLOAT
0.0e0 : E_FLOAT
5e-3 : E_FLOAT
3e23 : E_FLOAT
3E5 : E_FLOAT
-3E-12 : E_FLOAT
aether : STRING
1ee3 : STRING
buzz : STRING
eeep : STRING
121212beep : STRING

  1. [regex demo](https://regex101.com/r/J41gmM/1)
  3. </details>

huangapple
  • 本文由 发表于 2023年7月27日 22:42:30
  • 转载请务必保留本文链接：https://go.coder-hub.com/76780886.html
  • numpy
  • python
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