目录
Python中有序字典和无序字典，一键多值字典。
Python将字典内容写入json文件。
1、无序字典
目前了解三种，在Python中直接默认的是无序字典，这种不会按照你插入的顺序排序，即使你对字典排序后，返回的也是一个list变量，而不是字典，倘若你将这个list字典后，又会变回无序字典。
例子如下：
import operator
x = {\"label\": \"haha\", \"data\": 234, \"score\": 0.3}
sorted_x = sorted(x.items(), key=operator.itemgetter(0))
print x
print type(x)
print sorted_x
print type(sorted_x)
print dict(sorted_x)
2、有序字典
如果我们想保持字典按照我们插入的顺序有序怎么办？可以用OrderedDict来初始化字典。
例子如下：
from collections import OrderedDict x = OrderedDict() x[\"label\"] = \"haha\" x[\"data\"] = 234 x[\"score\"] = 0.3 print x print type(x)
3、一键多值字典
如果我们想用一键多值字典怎么办，可以使用defaultdict，例子如下：
from collections import defaultdict video = defaultdict(list) video[\"label\"].append(\"haha\") video[\"data\"].append(234) video[\"score\"].append(0.3) video[\"label\"].append(\"xixi\") video[\"data\"].append(123) video[\"score\"].append(0.7) print video print type(video)
4、写入json
字典内容写入json时，需要用json.dumps将字典转换为字符串，然后再写入。
json也支持格式，通过参数indent可以设置缩进，如果不设置的话，则保存下来会是一行。
例子：
4.1 无缩进
from collections import defaultdict, OrderedDict
import json
video = defaultdict(list)
video[\"label\"].append(\"haha\")
video[\"data\"].append(234)
video[\"score\"].append(0.3)
video[\"label\"].append(\"xixi\")
video[\"data\"].append(123)
video[\"score\"].append(0.7)
test_dict = {
\'version\': \"1.0\",
\'results\': video,
\'explain\': {
\'used\': True,
\'details\': \"this is for josn test\",
}
}
json_str = json.dumps(test_dict)
with open(\'test_data.json\', \'w\') as json_file:
json_file.write(json_str)
4.2 有缩进
from collections import defaultdict, OrderedDict
import json
video = defaultdict(list)
video[\"label\"].append(\"haha\")
video[\"data\"].append(234)
video[\"score\"].append(0.3)
video[\"label\"].append(\"xixi\")
video[\"data\"].append(123)
video[\"score\"].append(0.7)
test_dict = {
\'version\': \"1.0\",
\'results\': video,
\'explain\': {
\'used\': True,
\'details\': \"this is for josn test\",
}
}
json_str = json.dumps(test_dict, indent=4)
with open(\'test_data.json\', \'w\') as json_file:
json_file.write(json_str)
方法补充
下面是参考上文代码整理出的另一种实现方法，可以参考一下
\"\"\"
将整个数据集分为train和test，相应的也分别分配整个json文件
\"\"\"
import os
import random
import json
total_select_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\train\\yuedongguan_select\"
total_json_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\train\\yuedongguan.json\"
test_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\test\\has_yiliuwu\\yuedongguan_test\"
test_json_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\test\\has_yiliuwu\\yuedongguan_test\\yuedongguan_test.json\"
train_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\train\\yuedongguan\"
train_json_path = r\"C:\\Users\\9ling\\Desktop\\YiLiuWuDataset\\train\\yuedongguan\\yuedongguan.json\"
data = json.load(open(total_json_path))[\"labels\"]
# test_data = json.load(open(test_json_path))[\"labels\"]
all_select_path = os.listdir(total_select_path)
all_file_path = [] # 待分配的图片路径
for item in all_select_path:
file_path = os.path.join(total_select_path, item)
all_file_path.append(file_path)
# print(all_file_path)
idx = [i for i in range(len(all_select_path))]
random.shuffle(idx) # 在idx上改变
def copy_dir(src_path, target_path): # src_path原文件，target_path目标文件
if os.path.isdir(src_path) and os.path.isdir(target_path):
filelist_src = os.listdir(src_path)
for file in filelist_src:
path = os.path.join(os.path.abspath(src_path), file)
if os.path.isdir(path):
path1 = os.path.join(os.path.abspath(target_path), file)
if not os.path.exists(path1):
os.mkdir(path1)
copy_dir(path, path1)
else:
with open(path, \'rb\') as read_stream:
contents = read_stream.read()
path1 = os.path.join(target_path, file)
with open(path1, \'wb\') as write_stream:
write_stream.write(contents)
return True
else:
return False
test_data_dir = {\"labels\": []}
for item in idx[:41]:
with open(all_file_path[item], \'rb\') as read_stream:
contents = read_stream.read()
path1 = os.path.join(test_path, all_file_path[item].split(\"\\\\\")[-1]) # 测试集图片的路径
with open(path1, \'wb\') as write_stream:
write_stream.write(contents)
for s in data:
if s[\"filename\"].split(\"\\\\\")[-1] == all_file_path[item].split(\"\\\\\")[-1]:
test_data_dir[\"labels\"].append(s)
# print(s)
json_test_str = json.dumps(test_data_dir, indent=4)
with open(test_json_path, \'w\') as json_file:
json_file.write(json_test_str)
print(test_data_dir)
print(len(test_data_dir[\"labels\"]))
print(\"*\"*30)
train_data_dir = {\"labels\": []}
for item in idx[41:]:
with open(all_file_path[item], \'rb\') as read_stream:
contents = read_stream.read()
path2 = os.path.join(train_path, all_file_path[item].split(\"\\\\\")[-1])
with open(path2, \'wb\') as write_stream:
write_stream.write(contents)
for s1 in data:
if s1[\"filename\"].split(\"\\\\\")[-1] == all_file_path[item].split(\"\\\\\")[-1]:
train_data_dir[\"labels\"].append(s1)
json_train_str = json.dumps(train_data_dir, indent=4)
with open(train_json_path, \'w\') as json_file:
json_file.write(json_train_str)
print(train_data_dir)
print(len(train_data_dir[\"labels\"]))
# print(s)
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