Python学習ノート==pythonをすばやく理解
61191 ワード
1 def buildConnectionString(params):
2 """Build a connection string from a dictionary of parameters.
3
4 Returns string."""
5 return ";".join(["%s=%s" % (k, params[k]) for k in params.keys()])
6
7 if __name__ == "__main__":
8 myParams = {"server":"mpilgrim", \
9 "database":"master", \
10 "uid":"sa", \
11 "pwd":"secret" \
12 }
13 print buildConnectionString(myParams) 1 >>> d = {"server":"mpilgrim", "database":"master"}# ，# d， {} ， ；
2 >>> d
3 {'database': 'master', 'server': 'mpilgrim'}
4 >>> d['server'] #
5 'mpilgrim'
6 >>> d['database']
7 'master'
8 >>> d['mpilgrim'] #
9 Traceback (most recent call last):
10 File "<stdin>", line 1, in <module>
11 KeyError: 'mpilgrim'>>> d["server"]="test" # ，
>>> d
{'database': 'master', 'server': 'test'}
>>> d["new"] = "start" #
>>> d
{'new': 'start', 'database': 'master', 'server': 'test'}辞書には順序の概念がない.
>>> d
{'new': 'start', 'database': 'master', 'server': 'test'}
>>> d["sj"]=3
>>> d
{'new': 'start', 'sj': 3, 'database': 'master', 'server': 'test'}
>>> d[2]="sta"
>>> d
{'new': 'start', 'sj': 3, 'database': 'master', 2: 'sta', 'server': 'test'}>>> d
{'new': 'start', 'sj': 3, 'database': 'master', 2: 'sta', 'server': 'test'}
>>> del d[2] #
>>> d
{'new': 'start', 'sj': 3, 'database': 'master', 'server': 'test'}
>>> d.clear() # ，
>>> d
{}>>> li = ["a", "b", "test", "shabi", "helmet"] #5
>>> li
['a', 'b', 'test', 'shabi', 'helmet']
>>> li[0] #
'a'
>>> li[4]
'helmet'>>> li
['a', 'b', 'test', 'shabi', 'helmet']
>>> li[-5] # li[n]=li[n-len(li)]
'a'
>>> li[-1] # li[-1]
'helmet'>>> li
['a', 'b', 'test', 'shabi', 'helmet']
>>> li[0:3] # ，li 0 2 3
['a', 'b', 'test']
>>> li[1:-1]
['b', 'test', 'shabi']>>> li
['a', 'b', 'test', 'shabi', 'helmet']
>>> li[:3]
['a', 'b', 'test']
>>> li[0:]
['a', 'b', 'test', 'shabi', 'helmet']
>>> li[:]
['a', 'b', 'test', 'shabi', 'helmet']>>> li
['a', 'b', 'test', 'shabi', 'helmet']
>>> li.append("elimination") #append
>>> li
['a', 'b', 'test', 'shabi', 'helmet', 'elimination']
>>> li.insert(2, "elinination") #insert
>>> li
['a', 'b', 'elinination', 'test', 'shabi', 'helmet', 'elimination']
>>> li.extend(["shi", "shang"]) #extend
>>> li
['a', 'b', 'elinination', 'test', 'shabi', 'helmet', 'elimination', 'shi', 'shang']>>> li
['b', 'elinination', 'test', 'shabi', 'helmet', 'elimination', 'shi', 'shang']
>>> li.index("b")
0
>>> li.index('c')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: 'c' is not in list
>>> "c" in li # false
False>>> li
['b', 'elinination', 'test', 'shabi', 'helmet', 'elimination', 'shi', 'shang']
>>> li.remove('b') #
>>> li
['elinination', 'test', 'shabi', 'helmet', 'elimination', 'shi', 'shang']
>>> li.remove('c')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ValueError: list.remove(x): x not in list
>>> li.pop() #
'shang'
>>> li
['elinination', 'test', 'shabi', 'helmet', 'elimination', 'shi']>>> li = ["a", "b", "mpilgrim"]
>>> li = li + ["new", "test"] # extend(otherlist), + ,extend()
>>> li
['a', 'b', 'mpilgrim', 'new', 'test']
>>> li += ["two"] #
>>> li
['a', 'b', 'mpilgrim', 'new', 'test', 'two']
>>> li = [1, 2] * 3
>>> li
[1, 2, 1, 2, 1, 2]>>> t = ("a", "b", 4, "z", "example")
>>> t
('a', 'b', 4, 'z', 'example')
>>> t[0]
'a'
>>> t[-1]
'example'
>>> t[1:3]
('b', 4)>>> t.append("new")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'append'
>>> t.insert("new")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'insert'
>>> t.indes("z")
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: 'tuple' object has no attribute 'indes'
>>> "z" in t # in
Trueif __name__ == "__main__":
myParams = {"server":"mpilgrim", \
"database":"master", \
"uid":"sa", \
"pwd":"secret" \
}>>> x
Traceback (innermost last):
File "<interactive input>", line 1, in ?
NameError: There is no variable named 'x'
>>> x = 1
>>> x
1return ";".join(["%s=%s" % (k, params[k]) for k in params.keys()])>>> pwd = "secret"
>>> print pwd + "is the first" #
secretis the first
>>> print "%s is the test" % (pwd,) #
secret is the test
>>> userCount = 6
>>> print "%d" % (userCount,)
6
>>> print "Users connected: " + userCount # #
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: cannot concatenate 'str' and 'int' objects["%s=%s" % (k, params[k]) for k in params.keys()]
# params keys ， >>> li=[2,4,6,8]
>>> [elem*2 for elem in li] #python ， ， elem， elem*2,
[4, 8, 12, 16]
>>> li #
[2, 4, 6, 8]>>> params={"server":"mpilgrim", "database":"master", "uid":"sa", "pwd":"secret"}
>>> [k for k in params.keys()] # ， ， params,keys().
['pwd', 'database', 'uid', 'server']
>>> [params[k] for k in params.keys()] # ， params[k]， k ， ， params.values()。
['secret', 'master', 'sa', 'mpilgrim']
>>> ["%s=%s" % (k, params[k]) for k in params.keys()] # ， 。
['pwd=secret', 'database=master', 'uid=sa', 'server=mpilgrim']>>> params = {"shi":"shang", "zhu":"xing", "shi":"qiang"}
>>> params.keys() # ， ， # ， ， ， #
['shi', 'zhu']return ";".join(["%s=%s" % (k, params[k]) for k in params.keys()]) #join >>> params={"server":"mpilgrim", "database":"master", "uid":"sa", "pwd":"secret"}
>>> s = ";".join(params)
>>> s
'pwd;database;uid;server'
>>> s.split(":")
['pwd;database;uid;server']
>>> s.split(";")
['pwd', 'database', 'uid', 'server']
>>> s.split(";", 1) # ； ， ，
['pwd', 'database;uid;server'] 1 def buildConnectionString(params):
2 """Build a connection string from a dictionary of parameters.
3
4 Returns string."""
5 return ";".join(["%s=%s" % (k, params[k]) for k in params.keys()])
6
7 if __name__ == "__main__":
8 myParams = {"server":"mpilgrim", \
9 "database":"master", \
10 "uid":"sa", \
11 "pwd":"secret" \
12 }
13 print buildConnectionString(myParams)
14
15 # ：
16 server=mpilgrim;uid=sa;database=master;pwd=secret本文まとめノート参考自:dive in to python