Question

我有2列。

RAB10   -0.016575
MEF2C   -0.019655
SP2 1.24E-01
SP2 -0.18870625
SP2 0.0879425

我想输出

RAB10   -0.016575
MEF2C   -0.019655
SP2 1.24E-01
    -0.18870625
    0.0879425

对于重复键，我只能得到1个键和所有相应的值。

我为它编写了这段代码：

import math
import numpy
import csv
import collections
from decimal import *
from collections import defaultdict
with open('output.csv','rb') as file:
  contents = csv.reader(file)
  #storing content of Common genes Result edited file in matrix
  matrix = list()
  for row in contents:
    matrix.append(row)

#to get both the index and the item
for index, item in enumerate(matrix):
#to access 2nd column value
   first_column = [ row[0] for row in matrix ]
   second_column = [ row[1] for row in matrix
for q, a in zip (first_column, second_column):
        if q==q
        print (Format (q,a))

此代码仅返回键和值，但不将值与1个重复键合并。

Answer 1

您需要实际使用默认值，附加值。

from collections import defaultdict
d = defaultdict(list)
with open('output.csv') as f:
    for line in f: # loop over each line
        spl = line.split() # split , "RAB10   -0.016575" -> ["RAB10","-0.016575"]
        d[spl[0]].append(spl[1]) # append value
print(d)
defaultdict(<type 'list'>, {'MEF2C': ['-0.019655'], 'RAB10': ['-0.016575'], 'SP2': ['1.24E-01', '-0.18870625', '0.0879425']})

如果您希望值为float，请使用d[spl[0]].append(float(spl[1]))，但前提是您确定所有数据的格式相同，否则您需要try/except块。

from collections import defaultdict
d = defaultdict(list)
with open("output.csv") as f:
    for line in f:
        spl = line.split()
        try:
            d[spl[0]].append(float(spl[1]))
        except (ValueError,IndexError): # catch lines that don't have at least two elements or the second element is not a float
            continue

Answer 2

一旦你有了Padraic Chunningham的答案中的defaultdict d，就可以轻松打印出来了：

for key, values in sorted(d.iteritems()):
  values_iter = iter(values)
  print('%s\t%s' % (key, values_iter.next()):
  for value in values_iter:
    print('\t%s' % value)

或者，更紧凑：

for key, values in sorted(d.iteritems()):
  print('%s\t%s' % (key, '\n\t'.join(values)))

在Python 3中，您需要.items()而不是.iteritems()。

访问多个值对1个重复键

2 个答案: