Python数据分析实例五、US 大选捐款数据分析
美国联邦选举委员会 （FEC） 公布了对政治竞选活动的贡献数据。这包括投稿人姓名、职业和雇主、地址和投款金额。2012 年美国总统大选的贡献数据以单个 150 MB 的 CSV 文件P00000001-ALL.csv形式提供，该文件可以通过以下pandas.read_csv加载：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-ALL.csv", low_memory=False)
print(fec.info())
print(fec.iloc[123]) # 示例记录加载成DataFrame输出该对象内容信息：
这个DataFrame 中的示例记录如下所示：
数据中没有政党隶属关系，因此添加此关系数据非常有用。可以使用 unique 获取所有唯一政治候选人的列表：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-ALL.csv", low_memory=False)
unique_cands = fec["cand_nm"].unique()
print(unique_cands)
print(unique_cands[2])unique_cands 输出：
['Bachmann, Michelle' 'Romney, Mitt' 'Obama, Barack'
"Roemer, Charles E. 'Buddy' III" 'Pawlenty, Timothy' 'Johnson, Gary Earl'
'Paul, Ron' 'Santorum, Rick' 'Cain, Herman' 'Gingrich, Newt'
'McCotter, Thaddeus G' 'Huntsman, Jon' 'Perry, Rick']
unique_cands[2] 输出： Obama, Barack
我们使用字典来表示党派关系：
# 用字典表示候选人所属政党
parties = {"Bachmann, Michelle": "Republican",
"Cain, Herman": "Republican",
"Gingrich, Newt": "Republican",
"Huntsman, Jon": "Republican",
"Johnson, Gary Earl": "Republican",
"McCotter, Thaddeus G": "Republican",
"Obama, Barack": "Democrat",
"Paul, Ron": "Republican",
"Pawlenty, Timothy": "Republican",
"Perry, Rick": "Republican",
"Roemer, Charles E. 'Buddy' III": "Republican",
"Romney, Mitt": "Republican",
"Santorum, Rick": "Republican"}
现在，使用此字典映射和 Series 对象上的 map 方法，可以从候选人名字中计算政党数组：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-ALL.csv", low_memory=False)
print(fec.info())
print(fec.iloc[123]) # 示例记录
unique_cands = fec["cand_nm"].unique()
# 用字典表示候选人所属政党
parties = {"Bachmann, Michelle": "Republican",
"Cain, Herman": "Republican",
"Gingrich, Newt": "Republican",
"Huntsman, Jon": "Republican",
"Johnson, Gary Earl": "Republican",
"McCotter, Thaddeus G": "Republican",
"Obama, Barack": "Democrat",
"Paul, Ron": "Republican",
"Pawlenty, Timothy": "Republican",
"Perry, Rick": "Republican",
"Roemer, Charles E. 'Buddy' III": "Republican",
"Romney, Mitt": "Republican",
"Santorum, Rick": "Republican"}
print(fec["cand_nm"][123456:123461])
print(fec["cand_nm"][123456:123461].map(parties))
# 将政党关系映射作为party列添加到fec对象
fec["party"] = fec["cand_nm"].map(parties)
fec_party_count = fec["party"].value_counts()
print(fec_party_count)print(fec["cand_nm"][123456:123461]) 输出：
print(fec["cand_nm"][123456:123461].map(parties)) 输出：
print(fec_party_count) 输出：
准备几个数据准备点。此数据包括供款和退款，为了简化分析，我们将数据集限制为正贡献（捐款）。由于 Barack Obama 和 Mitt Romney 是主要的两位候选人，我们还准备一个子集，其中只包含对他们的竞选活动是有所贡献的数据子集：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-ALL.csv", low_memory=False)
print(fec.info())
print(fec.iloc[123]) # 示例记录
unique_cands = fec["cand_nm"].unique()
# 用字典表示候选人所属政党
parties = {"Bachmann, Michelle": "Republican",
"Cain, Herman": "Republican",
"Gingrich, Newt": "Republican",
"Huntsman, Jon": "Republican",
"Johnson, Gary Earl": "Republican",
"McCotter, Thaddeus G": "Republican",
"Obama, Barack": "Democrat",
"Paul, Ron": "Republican",
"Pawlenty, Timothy": "Republican",
"Perry, Rick": "Republican",
"Roemer, Charles E. 'Buddy' III": "Republican",
"Romney, Mitt": "Republican",
"Santorum, Rick": "Republican"}
# 将政党关系映射作为party列添加到fec对象
fec["party"] = fec["cand_nm"].map(parties)
fec_party_count = fec["party"].value_counts()
temp = (fec["contb_receipt_amt"] > 0).value_counts()
print(temp)
fec = fec[fec["contb_receipt_amt"] > 0]
fec_mrbo = fec[fec["cand_nm"].isin(["Obama, Barack", "Romney, Mitt"])]一、按职业及雇主划分的捐款统计数字
按职业划分的捐款量是一个经常被研究的统计数据。例如，律师倾向于向民主党人捐赠更多的钱，而企业高管倾向于向共和党人捐赠更多。首先，按职业划分的捐赠总数可以用 value_counts 计算：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-ALL.csv", low_memory=False)
#print(fec.info())
#print(fec.iloc[123]) # 示例记录
unique_cands = fec["cand_nm"].unique()
# 用字典表示候选人所属政党
parties = {"Bachmann, Michelle": "Republican",
"Cain, Herman": "Republican",
"Gingrich, Newt": "Republican",
"Huntsman, Jon": "Republican",
"Johnson, Gary Earl": "Republican",
"McCotter, Thaddeus G": "Republican",
"Obama, Barack": "Democrat",
"Paul, Ron": "Republican",
"Pawlenty, Timothy": "Republican",
"Perry, Rick": "Republican",
"Roemer, Charles E. 'Buddy' III": "Republican",
"Romney, Mitt": "Republican",
"Santorum, Rick": "Republican"}
# 将政党关系映射作为party列添加到fec对象
fec["party"] = fec["cand_nm"].map(parties)
fec_party_count = fec["party"].value_counts()
temp = (fec["contb_receipt_amt"] > 0).value_counts()
#print(temp)
fec = fec[fec["contb_receipt_amt"] > 0]
fec_mrbo = fec[fec["cand_nm"].isin(["Obama, Barack", "Romney, Mitt"])]
# 按职业划分 统计捐赠量 由于数据量太大取前10个观察
temp10 = fec["contbr_occupation"].value_counts()[:10]
print(temp10)输出按职业划分统计的捐赠量（前10个）：
从上面的职业输出可以看出，许多人的职业名称虽然不同，但指的是相同的基本工作类型。下面我们用代码实现从一个职业映射到另一个职业来，清理其中一些相同类型职业。请注意下面代码中使用 dict.get 允许没有映射的职业也能“传递”的 “技巧”：
import pandas as pd
fec = pd.read_csv("datasets/fec/P00000001-