for循环没有正确地迭代python。

Question

我不知道我做错了什么，但我的for循环没有按照我想要的方式工作。

import re

liste  = ["train_seg/aoi105_c1_20_A", "train_seg/aoi105_c1_30_A", "train_seg/aoi105_c1_30_B", 
          "train_seg/aoi98_c1_20_A", "train_seg/aoi98_c1_30_A", "train_seg/aoi98_c1_30_B", 
          "train_classes/aoi98_c1_20_A", "train_classes/aoi98_c1_30_A", "train_classes/aoi98_c1_30_B",
         "train_classes/aoi105_c1_20_A", "train_classes/aoi105_c1_30_A", "train_classes/aoi105_c1_30_B"]

cat = ["c1"]
seg = ["20", "30"]
com = ["A", "B"]

for x in cat:
    for y in seg:
        for z in com:
            if y == "20" and z == "B":
                continue
            #print(x,y,z)
            
            for s in liste:
                if all(a in s for a in ["aoi105", x, y, z]):
                    #print(s)
                    
                    if re.findall("train_seg", s):
                        print(s)
                        
                    if re.findall("train_classes", s):
                        print(s)
                        
                if all(a in s for a in ["aoi98", x, y, z]):
                    #print(s)

                    if re.findall("train_seg", s):
                        print(s)

                    if re.findall("train_classes", s):
                        print(s)

我希望列表中的元素"liste“按以下顺序计算：

train_seg/aoi105_c1_20_A
train_classes/aoi105_c1_20_A
train_seg/aoi98_c1_20_A
train_classes/aoi98_c1_20_A

train_seg/aoi105_c1_30_A
train_classes/aoi105_c1_30_A
train_seg/aoi98_c1_30_A
train_classes/aoi98_c1_30_A

train_seg/aoi105_c1_30_B
train_classes/aoi105_c1_30_B
train_seg/aoi98_c1_30_B
train_classes/aoi98_c1_30_B

为什么每一行都没有按正确的顺序进行评估？我希望train_seg和train_classes首先对每个数字进行评估。谢谢!

Answer 1

答案很简单。你差点就成功了。你增加了额外的打印语句，这导致了问题的出现。

import re

cat = ["c1"]
seg = ["20", "30"]
com = ["A", "B"]
tag = ["aoi105","aoi98"]
for x in cat:
    for y in seg:
        for z in com:
            for i in tag:
                if y == "20" and z == "B":
                    continue            
                for s in liste:                    
                    train_seg = f'''train_seg/{i}_{x}_{y}_{z}'''
                    train_classes = f'''train_classes/{i}_{x}_{y}_{z}'''
                    if re.findall(train_seg, s): print(s)                        
                    if re.findall(train_classes, s): print(s)

Answer 2

像这样循环，有那么多级别的嵌套循环，是以正确的顺序获得项目的一种迂回方式。它可能通过在for s in liste:之前添加第二个if all(a in s for a in ["aoi98", x, y, z]):来工作。

但我认为有一个更好的方法:显式地按所需的顺序对项目进行排序。类似这样的内容(为错误的变量命名道歉，这是由于我对问题域缺乏了解造成的)：

(编辑:更清晰和更短)

import re

liste  = ["train_seg/aoi105_c1_20_A", "train_seg/aoi105_c1_30_A", "train_seg/aoi105_c1_30_B", 
          "train_seg/aoi98_c1_20_A", "train_seg/aoi98_c1_30_A", "train_seg/aoi98_c1_30_B", 
          "train_classes/aoi98_c1_20_A", "train_classes/aoi98_c1_30_A", "train_classes/aoi98_c1_30_B",
         "train_classes/aoi105_c1_20_A", "train_classes/aoi105_c1_30_A", "train_classes/aoi105_c1_30_B"]

TRAIN_TYPES_ORDER = ['train_seg', 'train_classes']
AOIS_ORDER = ['aoi105', 'aoi98']
CATS_ORDER = ['c1']
SEGS_ORDER = ['20', '30']
COMS_ORDER = ['A', 'B']

def sort_key(item):
    train_type, aoi, cat, seg, com = re.fullmatch(r'(.*)/(.*)_(.*)_(.*)_(.*)', item).groups()
    return (
        COMS_ORDER.index(com),
        SEGS_ORDER.index(seg),
        CATS_ORDER.index(cat),
        AOIS_ORDER.index(aoi),
        TRAIN_TYPES_ORDER.index(train_type),
    )

sorted_items = sorted(liste, key=sort_key)
for item in sorted_items:
    print(item)