Python Csv-插入缺少的行

我有一个很大的文件，其中缺少一些行。这些数据需要以国家为基础

输入数据如下所示：

csv_str = """Type,Country,State,County,City,
1,USA,,,
2,USA,OH,,
3,USA,OH,Franklin,
4,USA,OH,Franklin,Columbus
4,USA,OH,Franklin,Springfield
4,USA,WI,Dane,Madison
"""

这需要：

csv_str = """Type,Country,State,County,City,
1,USA,,,
2,USA,OH,,
3,USA,OH,Franklin,
4,USA,OH,Franklin,Columbus
4,USA,OH,Franklin,Springfield
4,USA,WI,,
4,USA,WI,Dane,
4,USA,WI,Dane,Madison
"""

根据我的逻辑，键是

类型

字段，如果我找不到城市（类型4）的县（类型3），则插入一行，其中字段一直到县

县里也一样。如果我找不到一个县（类型3）的州（类型2），那么插入一行，该行的字段为State

由于我不了解python的功能，我尝试了更多的蛮力方法。这有点问题，因为我需要在同一个文件上进行大量迭代

我也尝试过谷歌精炼，但无法让它工作。手工操作很容易出错

谢谢你的帮助

import csv
import io

csv_str = """Type,Country,State,County,City,
1,USA,,,
2,USA,OH,,
3,USA,OH,Franklin,
4,USA,OH,Franklin,Columbus
4,USA,OH,Franklin,Springfield
4,USA,WI,Dane,Madison
"""
found_county =[]
missing_county =[]

def check_missing_county(row):
    found = False
    for elm in found_county:
        if elm.Type == row.Type:
            found = True
    if not found:
        missing_county.append(row)
        print(row)

reader = csv.reader(io.StringIO(csv_str))
for row in reader:
    check_missing_county(row)

---

根据我对这个问题的理解，我总结了以下几点：

import csv
import io

csv_str = u"""Type,Country,State,County,City,
1,USA,,,
2,USA,OH,,
3,USA,OH,Franklin,
4,USA,OH,Franklin,Columbus
4,USA,OH,Franklin,Springfield
4,USA,WI,Dane,Madison
"""

counties = []
states = []


def handle_missing_data(row):
    try:
        rtype = int(row[0])
    except ValueError:
        return []

    rtype = row[0]
    country = row[1]
    state = row[2]
    county = row[3]

    rows = []
    # if a state is present and it hasn't a row of it's own
    if state and state not in states:
        rows.append([rtype, country, state, '', ''])
        states.append(state)

    # if a county is present and it hasn't a row of it's own
    if county and county not in counties:
        rows.append([rtype, country, state, county, ''])
        counties.append(county)

    # if the row hasn't already been added add it now
    if row not in rows:
        rows.append(row)

    return rows

csvf = io.StringIO(csv_str)
reader = csv.reader(csvf)
for row in reader:
    new_rows = handle_missing_data(row)
    for new_row in new_rows:
        print new_row

---

那么你只想生成一份失踪国家的名单？