Question

字典应该有“N＆＃39; N＆＃39;关键之前＆＃39; D＆＃39;但是当它贯穿“D＆＃39;键是第一个，为什么追加函数将D添加到前面而不是字典的结尾？

Binary.txt是：

N = N D
N = D
D = 0
D = 1

python文件是

import sys
import string
from collections import defaultdict

#default length of 3
stringLength = 3

#get last argument of command line(file)
if len(sys.argv) == 1:
    #get a length from user
    try:
        stringLength = int(input('Length? '))
        filename = input('Filename: ')
    except ValueError:
        print("Not a number")

elif len(sys.argv) == 2:
    #get a length from user
    try:
        stringLength = int(input('Length? '))
        filename = sys.argv[1]
    except ValueError:
        print("Not a number")

elif len(sys.argv) == 3:
    filename = sys.argv[2]
    stringLength  = sys.argv[1].split('l')[1]
else:
    print("Invalid input!")





#checks

print(stringLength)
print(filename)

def str2dict(filename):
    result = defaultdict(list)
    with open(filename, "r") as grammar:
        #read file 
        lines = grammar.readlines()
        count = 0
        #loop through
        for line in lines:
            #append info 
            line = line.rstrip('\n')

            result[line[0]].append(line.split('=')[1])
            print(result)
    return result

Answer 1

标准dict是无序的。您应该使用collections.OrderedDict代替。

OrderedDict是一个记住首次插入密钥的顺序的字典。如果新条目覆盖现有条目，则原始插入位置保持不变。删除一个条目并重新插入它将把它移到最后。

Answer 2

来自Python Docs：

最好将字典视为无序一组键：值对[...]

（强调我的）。

Python字典追加是添加到字典前面而不是结尾

2 个答案: