Dictonary

dict.fromkeys(seq[, value])
seq = ('Google', 'Runoob', 'Taobao') 
dict = dict.fromkeys(seq) 
print "新字典为 : %s" % str(dict) 
dict = dict.fromkeys(seq, 10) 
print "新字典为 : %s" % str(dict)

https://www.runoob.com/python/att-dictionary-fromkeys.html

Read all items in dictionary

for k,v in info.items():
	print('%s is %s'%(k,v))
for k in info2: # 这种方式效率比较高
	print(k,info2[k])

https://blog.csdn.net/weixin_33928137/article/details/93172887

如何预防不存在某些‘key’的情形

使用defaultdict

from collections import defaultdict


# Function to return a default
# values for keys that is not
# present
def def_value():
	return "Not Present value of the key"
	
# Defining the dict
d = defaultdict(def_value)
d["a"] = 1
d["b"] = 2

print(d["a"])
print(d["b"])
print(d["c"])

如果已经有了一个dict，可以这么做：

d = defaultdict(def_value, data_dict)

参考：
[1] https://www.geeksforgeeks.org/defaultdict-in-python/

获取某些key

marks = {'Physics':67, 'Maths':87}
print(marks.get('Physics'))

Output: 67

The syntax of get() is:

dict.get(key[, value])

key - key to be searched in the dictionary
value (optional) - Value to be returned if the key is not found. The default value is None.

参考：
[1] https://www.programiz.com/python-programming/methods/dictionary/get