如何从 Python 中的字符串中提取数字并返回一个列表？

Question

我正在尝试查找文本中的所有数字并将它们返回到浮点数列表中。

在正文中：

• 逗号用于分隔千位
• 几个连续的数字用逗号和空格隔开
• 数字可以附加到单词

text = "30feet is about 10metre but that's 1 rough estimate several numbers are like 2, 137, and 40 or something big numbers are like 2,137,040 or something"

我需要将输出作为浮点数列表返回，中间有逗号，但没有语音标记。

Eg. 
extract_numbers("1, 2, 3, un pasito pa'lante Maria")
    is [1.0, 2.0, 3.0]

不幸的是，我当前尝试的输出返回一个字符串：

def extract_numbers(text):
  nums = re.findall(r'\b\d{1,3}(?:,\d{3})*(?:\.\d+)?(?!\d)', text)
  
    return (("[{0}]".format( 
                       ', '.join(map(str, nums))))) 

extract_numbers(TEXT_SAMPLE)

如何返回列表中的数字？

Answer 1

您可以从匹配项中删除所有逗号，然后将结果映射到float

你可以使用

def extract_numbers(text):
  return [float(x.replace(',','')) for x in re.findall(r'\b\d{1,3}(?:,\d{3})*(?:\.\d+)?(?!\d)', text)]

见Python demo：

import re
 
TEXT_SAMPLE = "30feet is about 10metre but that's 1 rough estimate several numbers are like 2, 137, and 40 or something big numbers are like 2,137,040 or something"
 
def extract_numbers(text):
  return [float(x.replace(',','')) for x in re.findall(r'\b\d{1,3}(?:,\d{3})*(?:\.\d+)?(?!\d)', text)]
 
print(extract_numbers(TEXT_SAMPLE))

# => [30.0, 10.0, 1.0, 2.0, 137.0, 40.0, 2137040.0]

Answer 2

这是一个业余代码，但我想它可以工作

  text = """30feet is about 10metre but that's 1 rough estimate several
  numbers are like 2, 137, and 40 or something big numbers are like 2,
  137,040 or something"""
  def extract_numbers(text):
    numbers = ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
    _numbers = []
    a=0
    while(a<len(text)):
      i=text[a]
      if(i in numbers):
        number=""
        while(text[a] in numbers):
          number+=text[a]
          a+=1
        _numbers.append(number)
      else:
        a+=1
    float_numbers=list()
    for i in _numbers:
      float_numbers.append(float(i))
    return float_numbers
print(extract_numbers(text))

输出：[30.0, 10.0, 1.0, 2.0, 137.0, 40.0, 2.0, 137.0, 40.0]

Answer 3

这应该以干净的方式解决问题。

import re  
def extract_numbers(txt):
    return [float(r.replace(',', '')) for r in re.findall(r'[\d,]+', txt)]

它会首先查找并分组所有没有分隔的数字和逗号，然后它会返回数字。