Ivy Xu's Notes

Python

Tue, 25 Aug 2026 10:19:13 +0800

Consider the following code:

funs = [lambda: i for i in range(3)]
print([f() for f in funs])

The result it [2,2,2].

funs = [lambda i=i:i for i in range(3)]
print([f() for f in funs])

funs = (lambda: i for i in range(3))
print([f() for f in funs])

The result is [1,2,3].

def f(n, lst=[]):
 lst.append(n)
 return lst
print(f(1), f(2))

The result is [1,2], [1,2].

About JSON

Mon, 24 Aug 2026 20:51:30 +0800

JSON is the abbreviation for javascript object notation. It defines six data types, namely:

number
null
boolen
string
object
array

Serialize and deserialize json are quite common in programming. For example, we may want to handle the HTTP response from the RESTful APIs, or send a HTTP request.

In Python, the built-in serialize functions are json.dump(), json.dumps(), and deserialize functions are json.load() and json.loads(). Usually, we represent the json object as a dict in Python.