import csv
def partytoyear(): #this function associate the party; to the year it was served#
party_in_power = {}
with open("presidents.txt") as f:
reader = csv.reader(f)
for row in reader:
party = row[1]
for year in row[2:]:
我有以下python代码:
print {a:b for a in [1, 2] for b in [3, 4, 5]}
我希望能给我这样的东西:
{1:3, 1:4, 1:5, 2:3, 2:4, 2:5}
但它却给了我这样的答案:
{1: 5, 2: 5}
我也尝试过循环反转,就像
print {a:b for b in [3, 4, 5] for a in [1, 2]}
但它还是给了我错误的答案。我也在下面的列表中尝试了同样的理解:
print [(a, b) for a in [1, 2] for b in [3, 4, 5]]
就像预期的那样。
我对字典有什么遗漏?
python命
这就是我在python中搜索对象的方式。有没有更有效(更快,更简单)的方法呢?
Obs: A是一个已知对象。
for i in Very_Long_List_Of_Names:
if A == My_Dictionary[i]:
print: "The object you are looking for is ", i
break
public class Quote
{
public decimal Price { get; set; }
public string Symbol { get; set; }
}
public List<Quote> quotes =
new List<Quote>(){new Quote{Price=100.00,Symbol="AAPL"},
new Quote{Price=200.00,Symbol="GOOG"}}
List<string,Quo
我有以下代码来在日历上显示事件
Private scheduleData As New Dictionary(Of DateTime, String)(5)
Protected Sub Page_Load(sender As Object, e As System.EventArgs) Handles Me.Load
scheduleData.Add(New DateTime(2011, 1, 9), "Vacation Day")
scheduleData.Add(New DateTime(2011, 1, 18), "Bu
我试图玩字典,我可以通过dict set命令。使用此命令,我可以为现有键设置新值。
当我试图设置多个键的值时,就会得到"missing value to go with key"。
我试过两种方法
#keys list and then values list
dict set userinfo name age VIGNESH 23
#key and value pair
dict set userinfo name VIGNESH age 23
我查看了dict set的手册页,发现了以下内容
dict set dictionaryVariable key ?key ...
我尝试将不同长度的键值映射到一个值,并根据所提供的几个键中的任何一个返回值。 例如: public const string GetDataCenterUrls = "getDataCenterUrls";
public const string Get = "get";
public const string Search = "search";
public const string Upsert = "upsert";
public const string value1=
我通过python tutor运行这段代码,只是对键和值是如何交换的感到困惑。我也搞不清楚myDict[d[key]]对应的值是什么,因为我不确定[d[key]]中的d实际上是做什么的。
def dict_invert(d):
'''
d: dict
Returns an inverted dictionary according to the instructions above
'''
myDict = {}
for key in d.keys():
if d[key] in