如何逐行读取带有空格分隔值的文件

Question

我有一种不同类型的文件格式，在txt文件中包含数百万行。

我的文件格式是这样的：

12122.AA.K IRIR-93I3KD-OEPE-IE,6373,893939,09/12/2093,,N,EC,3838-38939-393
12123.AA.K KKKS-93I3KD-OEPE-IE,9393,039033,09/12/2093,,N,EC,3838-38939-393
12122.AA.K PEOEP-93I3KD-OEPE-IE,9033,930392,09/12/2093,,N,EC,3838-38939-393
12124.AA.K MDJDK-93I3KD-OEPE-IE,3930,272882,09/12/2093,,N,EC,3838-38939-393
12125.AA.K EOEPE-93I3KD-OEPE-IE,8393,039393,09/12/2093,,N,EC,3838-38939-393

在 Python 中，我想将每一行拆分为一个键和一个值：

Key: 12122.AA.K
Value: IRIR-93I3KD-OEPE-IE,3833,343343,09/12/2093,,N,EC,3838-38939-393

如您所见，键和值仅由一个空格区分。

进入python的有效方法是什么？

Answer 1

with open(filename) as f:
    mapping = dict(line.split(' ', 1) for line in f) 

Answer 2

with open('file.txt','r') as file:
   thedict={e.split(' ')[0]:e.split(' ')[1] for e in file}

你可以试试这个字典理解

Answer 3

这将是矫枉过正，但您也可以使用内置的csv模块。

虽然默认情况下它设计为适用于逗号分隔值，但它确实提供了一种注册自定义方言以匹配自定义文件格式的方法，例如具有空格分隔值的文件。方言和格式参数包括一个delimiter属性，您可以在该属性中设置为空格" "。

import csv
from pprint import pprint
csv.register_dialect("my_custom_dialect", delimiter=" ")
mapping1 = {}
with open("test.txt") as f:
    reader = csv.reader(f, dialect="my_custom_dialect")
    for row in reader:
        # Each row is a list of strings separated by the delimiter
        key, value = row
        mapping1[key] = value
pprint(mapping1)

{'12122.AA.K': 'IRIR-93I3KD-OEPE-IE,6373,893939,09/12/2093,,N,EC,3838-38939-393',
 '12123.AA.K': 'KKKS-93I3KD-OEPE-IE,9393,039033,09/12/2093,,N,EC,3838-38939-393',
 '12124.AA.K': 'PEOEP-93I3KD-OEPE-IE,9033,930392,09/12/2093,,N,EC,3838-38939-393',
 '12125.AA.K': 'MDJDK-93I3KD-OEPE-IE,3930,272882,09/12/2093,,N,EC,3838-38939-393',
 '12126.AA.K': 'EOEPE-93I3KD-OEPE-IE,8393,039393,09/12/2093,,N,EC,3838-38939-393'}

如果您的文件具有标头，则可以利用 csv 的DictReader将每一行的值作为字典进行访问。

KEY VALUE
12122.AA.K IRIR-93I3KD-OEPE-IE,6373,893939,09/12/2093,,N,EC,3838-38939-393
12123.AA.K KKKS-93I3KD-OEPE-IE,9393,039033,09/12/2093,,N,EC,3838-38939-393
12124.AA.K PEOEP-93I3KD-OEPE-IE,9033,930392,09/12/2093,,N,EC,3838-38939-393

import csv
from pprint import pprint
csv.register_dialect("my_custom_dialect", delimiter=" ")
mapping2 = {}
with open("test_with_headers.txt") as f:
    reader = csv.DictReader(f, dialect="my_custom_dialect")
    for row in reader:
        # 'row' is a dictionary with the headers as the key
        mapping2[row["KEY"]] = row["VALUE"]
pprint(mapping2)

{'12122.AA.K': 'IRIR-93I3KD-OEPE-IE,6373,893939,09/12/2093,,N,EC,3838-38939-393',
 '12123.AA.K': 'KKKS-93I3KD-OEPE-IE,9393,039033,09/12/2093,,N,EC,3838-38939-393',
 '12124.AA.K': 'PEOEP-93I3KD-OEPE-IE,9033,930392,09/12/2093,,N,EC,3838-38939-393'}