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創建簡單的嵌套列表理解時遇到問題。每個級別的解包都不會從列表結構中正確刪除列表。下面的細節。無法爲嵌套列表理解解壓縮列表結構
file_list = ['genes1.csv', 'genes2.csv']
set_list = [('genes2.csv', (['A2LD1', 'A1BG', 'A2ML1', 'A1CF', 'A2M', 'A2BP1'], [-0.95, 1.226, 3.473, 4.958, 6.645, 11.953])), ('genes1.csv', (['A2LD1', 'A1BG', 'A2ML1', 'A1CF', 'A2M', 'A2BP1'], [-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]))]
set_list.sort(key = lambda (x,y): file_list.index(x))
讓我們看一下排序set_list:
print '\nset_list sorted:', set_list
set_list sorted: [('genes1.csv', (['A2LD1', 'A1BG', 'A2ML1', 'A1CF', 'A2M', 'A2BP1'], [-0.529, 1.444, 3.133, 4.303, 6.387, 11.117])), ('genes2.csv', (['A2LD1', 'A1BG', 'A2ML1', 'A1CF', 'A2M', 'A2BP1'], [-0.95, 1.226, 3.473, 4.958, 6.645, 11.953]))]
現在,我們要拉只值樣品1,在這種情況下,從genes1.csv值:
sample_1_values = []
for i, (j, k) in set_list[:1]:
for v in k:
sample_1_values.append(v)
print '\nsample 1 values:', sample_1_values
輸出:
sample 1 values: [-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]
現在的目標是創造sample_1_values爲嵌套列表理解:
sample_1_values = [[v for v in k] for i, (j, k) in set_list[:1]]
print '\nsample_1_values from list comprehension:', sample_1_values
和輸出:
[[-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]]
讓我們打破嵌套結構,第一:
s_list_comp_1 = [k for i, (j, k) in set_list[:1]]
print '\ninner list comprehension:', s_list_comp_1
print type(s_list_comp_1)
輸出:
inner list comprehension: [[-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]]
<type 'list'>
未發生拆箱。現在的外嵌套:
s_list_comp_2 = [v for v in s_list_comp_1]
print '\nouter list comprehension', s_list_comp_2
print type(s_list_comp_2)
輸出:
[[-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]]
<type 'list'>
同樣的問題,該名單尚未解開這個時候。隨着for語句和追加,我們看到它正確:
s_list_comp_2 = []
for v in s_list_comp_1:
for l in v:
s_list_comp_2.append(l)
print '\ncorrect unpacking:', s_list_comp_2
輸出:
correct unpacking: [-0.529, 1.444, 3.133, 4.303, 6.387, 11.117]
正確的拆包層次需要,我可以不使用嵌套列表理解複製的另一個層次。創建sample_1_values的整個表達式必須是嵌套的列表理解,以便稍後插入而不必佔用此佔位符。建議?
是的,完全正確,它使用for循環和追加給出與上面的sample_1_values相同的所需輸出。不知道你可以像這樣構造它。謝謝! – user2277435