Python 3.x 在循环中添加字典中相同键的值

我只是导入一个csv文件并将其转换为字典，还为不同的列指定了字段名。有人能教我如何在循环中添加字典中相同键的值吗

import csv


with open("breast_cancer_v1.csv", newline='') as file:


    fieldnames = ['1', '2','3','4','5','6','7','8','9','10','11']

    print ("1:  ID", "\n2:  Diagnosis", "\n3:  a) radius (mean of distances from center to points on the perimeter)", "\n4:  b) texture (standard deviation of gray-scale values)", "\n5:  c) perimeter", "\n6:  d) area", "\n7:  e) smoothness (local variation in radius lengths)", "\n8:  f) compactness (perimeter^2 / area - 1.0)", "\n9:  g) concavity (severity of concave portions of the contour)", "\n10: h) concave points (number of concave portions of the contour)", "\n11: i) symmetry", "\n12: j) fractal dimension (coastline approximation - 1)")

    csv_file = csv.DictReader(file, fieldnames)

    for row in csv_file:

        print(row)

示例：我希望将“3”列中的所有值相加，或计算“2”列中有多少个“B”。还在学习如何使用字典。导入csv后，我在循环中打印了我的字典，如下所示：

---

以

行['3']

的形式访问第3列，对于第2列，使用

行['2']

如果这不是为了学习字典，您一定要看看它的导入器功能。。。