Question

我需要从values文件中将常量名称及其对应的.txt提取到dictionary。 key = NameOfConstants和Value=float。

的位置

file的开头如下：

speed of light             299792458.0        m/s
gravitational constant     6.67259e-11        m**3/kg/s**2
Planck constant            6.6260755e-34      J*s
elementary charge          1.60217733e-19     C

如何轻松获取name常数？

这是我的尝试：

with open('constants.txt', 'r') as infile:
    file1 = infile.readlines()
    constants = {i.split()[0]: i.split()[1] for i in file1[2:]}

我没有使用split()做到正确，我需要稍微纠正一下！

Answer 1

{' '.join(line.split()[:-2]):' '.join(line.split()[-2:]) for line in lines}

Answer 2

从您的文本文件中我无法获得正确的空格值以进行拆分。所以下面的代码旨在帮助您。请看一下，它适用于您上述文件。

import string
valid_char = string.ascii_letters + ' '
valid_numbers = string.digits + '.'

constants = {}
with open('constants.txt') as file1:
    for line in file1.readlines():
        key = ''
        for index, char in enumerate(line):
            if char in valid_char:
                key += char
            else:
                key = key.strip()
                break
        value = ''

        for char in line[index:]:
            if char in valid_numbers:
                value += char
            else:
                break

        constants[key] = float(value)

print constants

Answer 3

您是否尝试过使用正则表达式？例如

([a-z]|\s)*

匹配一行的第一部分，直到常量的数字开始。

Python提供了一个非常好的正则表达式教程（正则表达式） https://docs.python.org/2/howto/regex.html

您也可以在线试用您的正则表达式 https://regex101.com/

Answer 4

re.split -

怎么样？

import re
lines = open(r"C:\txt.txt",'r').readlines()
for line in lines:
    data = re.split(r'\s{3,}',line)
    print "{0}  :  {1}".format(data[0],''.join(data[1:]))

或使用oneliner制作字典 -

{k:v.strip() for k,v in [(re.split(r'\s{3,}',line)[0],''.join(re.split(r'\s{3,}',line)[1:])) for line in open(r"C:\txt.txt",'r').readlines() ]}

输出 -

gravitational constant  :  6.67259e-11m**3/kg/s**2

Planck constant  :  6.6260755e-34J*s

elementary charge  :  1.60217733e-19C

词典 -

{'Planck constant': '6.6260755e-34J*s', 'elementary charge': '1.60217733e-19C', 'speed of light': '299792458.0m/s', 'gravitational constant': '6.67259e-11m**3/kg/s**2'}

Answer 5

with open('constants.txt', 'r') as infile:
    lines = infile.readlines()
    constants = {' '.join(line.split()[:-2]):float(' '.join(line.split()[-2:-1])) for line in lines[2:]}

由于上面不需要两行。

Answer 6

使用正则表达式最好解决这个问题。

专注于您的问题（如何获取姓名）和您的愿望（缩短时间）：

import re

# Regular expression fetches all characters
# until the first occurence of a number
REGEXP = re.compile('^([a-zA-Z\s]+)\d.*$')

with open('tst.txt', 'r') as f:

    for line in f:

        match = REGEXP.match(line)

        if match:

            # On a match the part between parentheses
            # are copied to the first group
            name = match.group(1).strip()

        else:

            # Raise something, or change regexp :)
            pass

如何将变量数据读入字典？

6 个答案: