我有一些代码，该代码应该抓取一个YAML文件并读入（成功完成），但也应该能够更新YAML返回值，这是以下三个选项之一：
第二个和第三个选项运行良好，但是每当我更新字典d中嵌套字典之外的任何值时，第一个返回TypeError: string indices must be integers或TypeError: 'int' object is not iterable。
这是我想出的代码：
class YAML_Config:
'''
Class used to interact with .YAML filetypes. Allows the creation of objects \
that can be manipulated and save certain YAML files and configuration settings.
'''
def __init__(self, filename):
'''
Initial defintion. Defines the location for saving a new .YAML file or for loading \
a previous one. The dictionary corresponding to the .YAML file is saved to self.dict. \
If this is a new .YAML file, an empty dictionary is created.
Input Arguments:
-filename: (string) The name of the file where the current .YAML file is \
located or the new .YAML will be saved.
'''
#Get the filename and save it to the class as a property.
self.file = filename
#Check if the file exists...
if os.path.isfile(self.file):
#Prepare to open the file with reading capabilities
with open(self.file,'r') as infile:
#Get a dictionary with all of the YAML informatin.
yaml_dict = yaml.load(infile)
#If the file does not exist...
else:
#Create an empty dictionary to save all YAML data.
yaml_dict = {}
#Create an empty .yaml file with the dictionary.
with open(self.file, 'w') as infile:
#Save updated dictionary to YAML file.
yaml.dump(yaml_dict, infile, default_flow_style=False)
print('YAML configuration file not found. New, empty dictionary, and .yaml file created.')
self.dict=yaml_dict
def update_value(self, kwargs):
'''
Used to update YAML files, and checks that the files were updated properly.
'''
#If these are not keyword arguments, then throw an error.
assert kwargs, 'Input Error'
#Get the YAML dictionary before it is updated.
yaml_dict = self.dict
#Make a copy of the dictionary to compare against later.
yaml_dict_original = copy.deepcopy(self.dict)
#Check if the dictionary is nonetype. This happens if the file is new as the file is empty.
if yaml_dict_original is None:
#Redefine orginal dictionary as an empty dictionary.
yaml_dict_original={}
#The new dictionary will simply be what is passed to the function.
yaml_dict=kwargs
else:
#Update the original dictionary and update it with the arguments passed.
#This also updates self.dict as yaml_dict is simply a reference to
#that dictionary, not a copy of it.
yaml_dict.update(kwargs)
#Check if changes were made
if (yaml_dict==yaml_dict_original) is False:
#Open the YAML file to write to it.
with open(self.file, 'w') as outfile:
#Save updated dictionary to YAML file.
yaml.dump(self.dict, outfile, default_flow_style=False)
#Check that the file actually updated properly:
#Double-check the file that it actually updated.
with open(self.file, 'r') as infile:
lastupdate = yaml.load(infile)
#Get any nonmatching values between what should be in the YAML file and what actually is.
errors = { k : yaml_dict[k] for k in set(yaml_dict) - set(lastupdate) }
#Find out what changed in the YAML file.
edits = { k : yaml_dict_original[k] for k in set(yaml_dict_original) - set(lastupdate) }
#Check if errors is not empty. Evaluating dictionaries as boolean either returns True (not empty)
#or False (empty).
if bool(errors) is True:
#First line of return print statement.
print('The following entries did not update successfully:')
#Loop through keys in errors
for n in errors:
#Print the current key
print (n)
#Loop through entries of current key
for m in errors[n]:
#Print current entry of current key
print (m,':',errors[n][m])
#Saved properly, check for edits and display to user.
else:
#Find where any edits were made.
edits = {k: yaml_dict_original[k] for k in yaml_dict_original if k in lastupdate and yaml_dict_original[k] != lastupdate[k]}
#Show user what edits were successfuly made.
print('%s was successfully updated with the following changes:' % os.path.basename(self.file))
#Loop through keys in edits
for n in edits:
#Print the current key
print (n)
#Loop through entries of current key
for m in edits[n]:
#Print current entry of current key
print (m,':',edits[n][m])
#If no changes were made...
else:
#Show user what edits were successfuly made.
print('No changes to %s were passed. File not updated.' %
os.path.basename(self.file))
test=YAML_Config(r'...Path\Python Work\yaml_test.yaml')
d = {'A': 7, 'B':{'C':'D', 'D':False, 'E':'Julio'},\
'The Real C': {'J?':'Yes, this is J.', 'K' : 241},'Q' : 'PQ'}
test.update_value(d)
第一个错误部分：
b = {'A': '', 'B':{'C':'D', 'D':False, 'E':'Julio'},\
'The Real C': {'J?':'Yes, this is J.', 'K' : 241},'Q' : 'PQ'}
#TypeError: string indices must be integers.
test.update_value(b)
第二个错误部分：
f = {'A': 7, 'B':{'C':'D', 'D':False, 'E':'Julio'},\
'The Real C': {'J?':'Yes, this is J.', 'K' : 241},'Q' : 2}
#TypeError: 'int' object is not iterable.
test.update_value(f)
每次运行此代码时，YAML文件都会更新。因此，实际的更新工作正常，但是我不确定为什么找不到字典更新的索引。我对Python有点生疏，对YAML还是陌生的，所以这里可能缺少明显的地方。
我正在使用Python 3.6.5。
答案 0 :(得分：1)
您的代码在此行上出错：
flutter:
uses-material-design: true
assets:
- images/myimagename.png
，此时flutter:
uses-material-design: true
assets:
- images/xxx.png
是字典： # Loop through entries of current key
for m in edits[n]:
（因为A是具有更改值的键）。您的代码似乎只预料到了一个复杂值的变化（例如edits的变化），因为如果您愿意这样做，
{A: 7}您得到：
B因此，您应该重新考虑您的“报告”，并将其更新为不仅可以处理b = {'A': 7, 'B':{'C':'D', 'D':True, 'E':'Julio'},\
'The Real C': {'J?':'Yes, this is J.', 'K' : 241},'Q' : 'PQ'}
s值，而且还可以处理test.yaml was successfully updated with the following changes:
B
C : D
D : False
E : Julio
s和基元的值（YAML标量：字符串，整数，布尔值）等）
dict，那么您的输出将是：
list（假设您依次运行两个额外的更新）。