從Python中讀取具有不同行和列大小的文本文件中的值

Question

我已閱讀其他simliar帖子，但它們似乎不適用於我的情況。因此，我在這裏重新發布它。

我有一個文本文件有不同的行和列的大小。我對具有特定參數的值行感興趣。例如。在下面的示例文本文件中，我想要在第二個位置具有數字「1」的每行的最後兩個值。也就是說，我想從值'101到104'開始的行中的值爲'1,101'，'101,2'，'2,102'和'102,3'，因爲它們具有數字'1'在第二個位置。

$MeshFormat 
2.2 0 8 
$EndMeshFormat 
$Nodes 
425 
. 
. 
$EndNodes 
$Elements 
630 
. 
97 15 2 0 193 97 
98 15 2 0 195 98 
99 15 2 0 197 99 
100 15 2 0 199 100 
101 1 2 0 201 1 101 
102 1 2 0 201 101 2 
103 1 2 0 202 2 102 
104 1 2 0 202 102 3 
301 2 2 0 303 178 78 250 
302 2 2 0 303 250 79 178 
303 2 2 0 303 198 98 249 
304 2 2 0 303 249 99 198 
. 
. 
. 
$EndElements 

的問題是，與我已經提出了下面提及的代碼時，它從「101」開始，但它從其它線路高達「304」或多個讀取值。我做錯了什麼或有人有更好的方法來解決這個問題？

# Here, (additional_lines + anz_knoten_gmsh - 2) are additional lines that need to be skipped 
# at the beginning of the .txt file. Initially I find out where the range 
# of the lines lies which I need. 
# The two_noded_elem_start is the first line having the '1' at the second position 
# and four_noded_elem_start is the first line number having '2' in the second position. 
# So, basically I'm reading between these two parameters. 


input_file = open(os.path.join(gmsh_path, "mesh_outer_region.msh")) 
output_file = open(os.path.join(gmsh_path, "mesh_skip_nodes.txt"), "w") 

for i, line in enumerate(input_file):             
    if i == (additional_lines + anz_knoten_gmsh + two_noded_elem_start - 2):   
     break 

for i, line in enumerate(input_file):            
    if i == additional_lines + anz_knoten_gmsh + four_noded_elem_start - 2:   
     break 

    elem_list = line.strip().split()     
    del elem_list[:5]        
    writer = csv.writer(output_file)    
    writer.writerow(elem_list)      

input_file.close() 
output_file.close() 

*編輯：用來尋找像two_noded_elem_start參數的一段代碼如下：

# anz_elemente_ueberg_gmsh is another parameter that is found out 
# from a previous piece of code and '$EndElements' is what 
# is at the end of the text file "mesh_outer_region.msh". 

input_file = open(os.path.join(gmsh_path, "mesh_outer_region.msh"), "r") 
for i, line in enumerate(input_file):      
    if line.strip() == anz_elemente_ueberg_gmsh: 
     break 

for i, line in enumerate(input_file):      
    if line.strip() == '$EndElements':      
     break 

    element_list = line.strip().split()     
    if element_list[1] == '1':        


     two_noded_elem_start = element_list[0]      
     two_noded_elem_start = int(two_noded_elem_start)    
     break 
input_file.close() 

Answer 1

>>> with open('filename') as fh:    # Open the file 
... for line in fh:      # For each line the file 
...  values = line.split()    # Split the values into a list 
...  if values[1] == '1':    # Compare the second value 
...   print values[-2], values[-1] # Print the 2nd from last and last 
1 101 
101 2 
2 102 
102 3