Question

我有一个像这样的列表

GroupID,Number
yellow,1
yellow,2
tan,0
blue,1
black,2
black,3

我想要的是这个

GroupID,Number
yellow,3
tan, 0
blue,1
black,5

所以我想添加与每个groupID相关联的数字。

这是我得到的，但结果陈述有困难：

from collections import defaultdict
d = defaultdict(list)
f = open("metal_modules.csv","r")
sheet = f.readlines()
#print sheet
for line in sheet[1:]:
#print line
spl = line.strip().split(",")
#print spl[1]
name = spl[0]
d[name].append(spl[1])

outfile = open("out.txt","w")
result = ""
for v in d.values():
     result = #here I need to sum the number in column two for each key in    the dictionary#
#print result
outfile.write(result)
f.close()
outfile.close()

Answer 1

保持简单

result = ""
for group in d:
    result += "%s, %s\n" % (group, sum(n for n in d[group]))

Answer 2

如果订单对您来说不是一个重要问题，您可以尝试以下方法。

from collections import defaultdict
with open('infile') as f:
    d = defaultdict(list)
    h = f.readline()
    m = f.readlines()
    for i in m:
        s = i.rstrip().split(',')
        d[s[0]].append(s[1])
with open('outfile', 'w') as w:
        w.write(h)
        for i in d.items():
            w.write(i[0]+","+str(sum(map(int,i[1])))+"\n")

Answer 3

看看以下内容：

with open("metal_modules.csv","r") as f:
  sheet = f.readlines()
  counter = {}
  for line in sheet[1:]:
    k,v = line.split(",")
    if k in counter:
      counter[k] += int(v)
    else:
      counter[k] = int(v)

with open("out.txt","w") as outfile:
  result = "GroupID,Number\n"
  for item in counter:
    result += "%s,%s\n" % (item,counter[item])
  outfile.write(result.strip())

计算与列表中的类别相关联的数字

3 个答案: