These one-liners are ok but a beginner might not get it. Here they are broken down:
list_of_dicts = [the list you posted]
Ok, we have a list, and each member of it is a dict. Here's a list comprehension:
[expr for d in list_of_dicts]
This is like saying for d in list_of_dicts .... expr is evaluated for each d and a new list is generated. You can also select just some of them with if, see the docs.
So, what expr do we want? In each dict d, we want the value that goes with the key 'memberId'. That's d['memberId']. So now
the list comprehension is:
[d['memberId'] for d in list_of_dicts]
This gives us a list of the email addresses, now to put them together with commas, we use join [see the docs]:
', '.join[[d['memberId'] for d in list_of_dicts]]
I see the other posters left out the [] inside join's argument list, and it works. Have to look that up, I don't know why you can leave it out. HTH.
Python has many data structures to work with, and each structure adds something to the table. Often we need to convert from one data structure to another to pass the data seamlessly.
Python Dictionary is a required container used in every code of day-to-day programming and web development. The more it is used, the more the requirement to master it; hence, knowledge of its operations is necessary.
To convert a dictionary to string in Python, use the json.dumps[] function. The json.dumps[] is a built-in function that converts a Python object into a json string.
# app.py
import json
stranger = {"Eleven": "Millie",
"Mike": "Finn",
"Will": "Noah"}
# print original dictionary
print["initial dictionary = ", stranger]
print[type[stranger]]
# convert dictionary into string
# using json.dumps[]
op = json.dumps[stranger]
# printing result as string
print["final string = ", op]
print["\n", type[op]]
Output
➜ pyt python3 app.py
initial dictionary = {'Eleven': 'Millie', 'Mike': 'Finn', 'Will': 'Noah'}
final string = {"Eleven": "Millie", "Mike": "Finn", "Will": "Noah"}
➜ pytFirst, we must print the original dictionary and its type in the above code. Then, we used json.dumps[] function to convert a dictionary to a string, and then we print the string and its data type.
Python dict to string using str[] function
Python str[] is a built-in function that converts the specified value into a string.
# app.py
stranger = {"Eleven": "Millie",
"Mike": "Finn",
"Will": "Noah"}
# print original dictionary
print["initial dictionary = ", stranger]
print[type[stranger]]
# convert dictionary into string
# using str[]
op = str[stranger]
# printing result as string
print["final string = ", op]
print["\n", type[op]]Output
➜ pyt python3 app.py
initial dictionary = {'Eleven': 'Millie', 'Mike': 'Finn', 'Will': 'Noah'}
final string = {'Eleven': 'Millie', 'Mike': 'Finn', 'Will': 'Noah'}
➜ pytFirst, we printed an original dictionary and its type in the above code. Then, we used the str[] function to convert the dictionary to string.
Python string to dictionary
To convert a string to a dictionary in Python, use the ast module’s literal.eval[] function. The ast.literal_eval[] is a ast library method that evaluates strings containing Python values from unknown sources without us having to parse the values.
import ast
stranger = '{"name": "Krunal", "age": "26"}'
# print original string
print["initial string = ", stranger]
print[type[stranger]]
# convert string into dictionary
# using ast.literal_eval[]
op = ast.literal_eval[stranger]
# printing result as string
print["final dictionary = ", op]
print["\n", type[op]]
Output
➜ pyt python3 app.py
initial string = {"name": "Krunal", "age": "26"}
final dictionary = {'name': 'Krunal', 'age': '26'}
➜ pytFirst, we printed the original string and its type and then used the ast.literal_eval[] function to convert the string to a dictionary, and then we printed the dictionary and its type.
That’s it for this tutorial.
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