Question

我有一个带有＆＃39; n＆＃39;的csv文件列。我需要获得rowcount 每列使用列名称并给出以下格式的字典：

csv_dict= {col_a:10,col_b:20,col_c:30}

其中10,20和30分别是col a，b和c的行数。我使用Dictreader的fieldnames选项获得了一个列列表。现在我需要列表中每列的行数。

这就是我的尝试：

for row in csv.DictReader(filename):
    col_count= sum(1 for row['col_a'] in re)+1

这只是得到列a的行数。如何获取列表中所有列的行数并以上述格式将它们放入字典中？任何帮助赞赏。谢谢和问候。

Answer 1

You can try this:
#Save this file with FileName.csv

Name,age,DOB
abhijeet,17,17/09/1990
raj,17,7/09/1990
ramesh,17,17/09/1990
rani,21,17/09/1990
mohan,21,17/09/1990
nil,25,17/09/1990

#Following is the python code.
import csv
from collections import defaultdict

columns = defaultdict(list) # each value in each column is appended to a list

with open('FileName.csv') as f:
    reader = csv.DictReader(f) # read rows into a dictionary format
    for row in reader: # read a row as {column1: value1, column2: value2,...}
        for (k,v) in row.items(): # go over each column name and value 
            if not v=='':
                columns[k].append(v) # append the value into the appropriate list
                                 # based on column name k

print len(columns['Name'])      #print the length of the specified column
print len(columns['age'])       #print the length of the specified column
print len(columns['DOB'])       #print the length of the specified column

Answer 2

我会用熊猫！

# FULLNAME= path/filename.extension of CSV file to read
data = pd.read_csv(FULLNAME, header=0)

# counting empty values
nan_values = data.isnull().sum()

# multiply by -1
ds = nan_values.multiply(-1)

# add total of rows from CSV
filled_rows = ds.add(len(data))

# create dict from data series
csv_dict = filled_rows.to_dict()

如果要保留列名称顺序，请使用OrderedDict

csv_dict_ordered = OrderedDict()
for idx in filled_rows.index:
    csv_dict_ordered[idx] = filled_rows[idx]

使用列名称的Python csv行计数

2 个答案: