如何遍历列表数组，检查每个列表中的元素并与值进行比较，如果它与值匹配则返回键

Question

我有一个包含数百个数组的数组，我正在尝试遍历每个数组并测试每个数组中的一个元素，以查看它是否存在于字典中。如果是这样，则返回与值匹配的键。这就是我卡住的地方。这就是我想要完成的目标。

dictionary = {'Bob' : '1', 'John' : '2', 'Andy': '3'}
list = [['5','2019','$50'],['1','2019','$50'],['5','2018','$50']
with open('C:/...','w',newline='') as f:
    fieldName = ['ID','Name','Price']
    writer = csv.DictWriter(f, fieldnames=fieldName)
    writer.writeheader()
    for i in list:
        if i[0] in dictionary.values():
            writer.writerow({'ID' : i[0], 'Name' : *DictionaryKey*, 'Price' : i[2]})

Answer 1

通过从值中搜索键来错误地使用字典：它应该是相反的。此外，可能有多个键对应于该值。

您的代码应在此 tmeplate 上：

dictionary = {'1': 'Bob', '2': 'John', '3': 'Andy'}
my_list = [['5','2019','$50'],['1','2019','$50'],['5','2018','$50'] # do not use 'list' as variable name
with open('C:/...','w+',newline='') as f:
    fieldNames = ['ID','Name','Price']  
    writer = csv.DictWriter(f, fieldnames=fieldNames)
    writer.writeheader()
    for id_, year, price in my_list:
        if id_ in dictionary.values():
            writer.writerow({'ID' : id_, 'Name' : dictionary[id_], 'Price' : price})

Answer 2

这是我问题的解决方案：

dictionary = {'1' : 'Bob', '2' : 'John', '2': 'Andy'}
my_list = [['5','2019','$50'],['1','2019','$50'],['5','2018','$50']]
with open('C:/...','w',newline='') as f:
fieldName = ['ID','Name','Price']
writer = csv.DictWriter(f, fieldnames=fieldName)
writer.writeheader()
for i in list:
  for key, value in dictionary:
      if i[0] == key:
           writer.writerow({'ID' : i[0], 'Name' : key, 'Price': i[2]})