Home / Questions / 428707
Accepted
Luis Desde Canada
Asked: 2022-02-17 08:55:45 +0800 CST 2022-02-17 08:55:45 +0800 CST

Loops with lists in Python

  • 772

I have a txt file with about 13000 lines, I'm importing them and when I want to make a loop to create a file with the information reordered as I need, I can't get it to work.

The file information is similar to this (the part with the line number is added for reference, it is not originally in the file):

Linea 0:    A     213992,"A     114416","05/01/2021","19/01/2021","N","E","1005","*                             "," 0"," 0","   0"," 0"," 0", \n
Linea 1:    A     114416,"Nombre 1                     ","*                                                 ","Address 1                     ","CAPITAL                       ","4682551534                     "," 74","F","1041","*                                                 ","   0","          ","     ","17/01/2013","17/01/2013","1202","1505254500070100                ","DNI", \n
Linea 2:    C,"37111662        ","01/05/1938","*                             ","2","*      ", \n
Linea 3:    G   
Linea 4:    A     213992,"            ","            ","                    ","                    ","                    ", 
Linea 5:    13
Linea 6:     1      475I 1
Linea 7:     2      941I 1
Linea 8:     3      190I 1
Linea 9:     4      192I 1
Linea 10:    5      412I 1
Linea 11:    6     4811I 1
Linea 12:    7      865I 1
Linea 13:    8      867I 1
Linea 14:    9      902I 1
Linea 15:   10     8298I 1
Linea 16:   11      546I 1
Linea 17:   12      711I 1
Linea 18:   13      120N 1
Linea 19:   A     213993,"A     129320","05/01/2021","12/01/2021","N","E","1005","*                             "," 0"," 0","   0"," 0"," 0", 
Linea 20:   A     129320,"Nombre 2                   ","*                                                 ","Address 2              ","CAPITAL                       ","4601555620  11531906         "," 73","F","   0","DNI 5564842                                       ","   0","          ","     ","05/01/2021","05/01/2021","1005","1504600761690600                ","DNI", 
Linea 21:   C,"569456742        ","11/10/1947","*                             ","2","*      ", 
Linea 22:   G   
Linea 23:   A     213993,"            ","            ","                    ","                    ","                    ", 
Linea 24:   12
Linea 25:    1      475I 1
Linea 26:    2      653I 1
Linea 27:    3      746I 1
Linea 28:    4      133I 1
Linea 29:    5      192I 1
Linea 30:    6      362I 1
Linea 31:    7      412I 1
Linea 32:    8     4811I 1
Linea 33:    9      546I 1
Linea 34:   10      902I 1
Linea 35:   11      948I 1
Linea 36:   12      120N 1
Linea 37:   A     214012,"A     129321","04/01/2021","18/01/2021","N","E","1005","*                             "," 0"," 0","   0"," 0"," 0", 
Linea 38:   A     129321,"Nombre 3                   ","*                                                 ","Address 3               ","CAPITAL                       ","1123101950                    "," 86","F","   0","DNI 16561081                                      ","   0","          ","     ","04/01/2021","04/01/2021","1005","1505370046050100                ","DNI", 
Linea 39:   C,"16561       ","02/03/1934","*                             ","2","*      ", 
Linea 40:   G   
Linea 41:   A     214012,"            ","            ","                    ","                    ","                    ", 
Linea 42:   11
Linea 43:    1      475I 1
Linea 44:    2      192I 1
Linea 45:    3      297I 1
Linea 46:    4      412I 1
Linea 47:    5     4811I 1
Linea 48:    6      546I 1
Linea 49:    7      865I 1
Linea 50:    8      866I 1
Linea 51:    9      867I 1
Linea 52:   10      500I 1
Linea 53:   11     8298I 1
Linea 54:   A     214013,"A     125271","04/01/2021","13/01/2021","N","E","1005"," 136                          "," 0"," 0","   0"," 0"," 0", 
Linea 55:   A     125271,"Nombre 4                  ","*                                                 ","Address 4                 ","CAPITAL                       ","4605-5813                     "," 69","M"," 136","DNI 6151369                                       ","   0","          ","     ","27/10/2017","27/10/2017","1005","1506000320150300                ","DNI", 
Linea 56:   C,"61546369        ","01/11/1948","*                             ","2","*      ", 
Linea 57:   G   
Linea 58:   A     214013,"            ","            ","                    ","                    ","                    ", 
Linea 59:   2
Linea 60:    1      412I 1
Linea 61:    2      500I 1

From line 0 I need element 0 and 2, from line 1 field 1, from line 2 field 16 to that I concatenate 475 from l6. This has to be done the number of times that line 5 says .

There you have to start again with the process in line 19 (which would become 0) and thus go through the 13000 lines...

The result should be:

A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,475
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,941
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,190
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,192
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,412
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,4811
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,865
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,867
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,902
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,8298
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,546
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,711
A213992,05/01/2021,070100      ,  ,Nombre 1                     ","*,120
A213992,05/01/2021,070100      ,  ,Nombre 2                     ","*,475
A213992,05/01/2021,070100      ,  ,Nombre 2                     ","*,653
A213992,05/01/2021,070100      ,  ,Nombre 2                     ","*,746

But Name 1 should be about 13 lines (q is variable, and is what defines the number of lines to print per Name), there it should jump to Name 2 recalculating the r0(initial line) and putting the substrings of the first 3 lines concatenated with the q lines that follow.

Surely there is an easier way to do it than the loop I did and it doesn't work, and that is the following:

with open ("E:\SkyDrive\A Files\A Files\LACVI\Datos LABSYS\PROT2101 test - COPY.txt", "r") as filename:

   lines = filename.readlines()

cantidad=len(lines)  


r0 = 0
q = int(lines[r0+5])
t = r0 + 6
print (q , t)

while r0 < r0+q+t:

   linea1 = lines[r0]
   r0 = r0+1
   linea2 = lines[r0]
   r0 = r0+5
   linea3 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea3[4:12].strip(), sep=",")
linea4 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea4[4:12].strip(), sep=",")
linea5 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea5[4:12].strip(), sep=",")
linea6 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea6[4:12].strip(), sep=",")
linea7 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea7[4:12].strip(), sep=",")
linea8 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea8[4:12].strip(), sep=",")
linea9 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea9[4:12].strip(), sep=",")
linea10 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea10[4:12].strip(), sep=",")
linea11 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea11[4:12].strip(), sep=",")
linea12 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea12[4:12].strip(), sep=",")
linea13 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea13[4:12].strip(), sep=",")
linea14 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea14[4:12].strip(), sep=",")
linea15 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea15[4:12].strip(), sep=",")
linea16 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea16[4:12].strip(), sep=",")
linea17 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea17[4:12].strip(), sep=",")
linea18 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea18[4:12].strip(), sep=",")
linea19 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea19[4:12].strip(), sep=",")
linea20 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea20[4:12].strip(), sep=",")
linea21 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea21[4:12].strip(), sep=",")
linea22 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea22[4:12].strip(), sep=",")
linea23 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea23[4:12].strip(), sep=",")
linea24 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea24[4:12].strip(), sep=",")
linea25 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea25[4:12].strip(), sep=",")
linea26 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea26[4:12].strip(), sep=",")
linea27 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea27[4:12].strip(), sep=",")
linea28 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea28[4:12].strip(), sep=",")
linea29 = lines[r0]
   r0 = r0+1
   print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea29[4:12].strip(), sep=",")
linea30 = lines[r0]
  r0 = r0+1
  print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea30[4:12].strip(), sep=",")
linea31 = lines[r0]
  print(linea1[1:13].replace(" ", ""),linea1[31:41],linea2[342:354],linea2[354:356],linea2[16:50].rstrip(),linea31[4:12].strip(), sep=",")

   r0=q+7
   print(r0)
   break'''

I don't know if there is an easier way to create the lines to print (for now it's the one I found), I'm just starting out and I don't understand why the loop doesn't work.

python-3.x

1 Answers

  1. Best Answer

    I think I have understood what you are looking for, but the information you give in the question is wrong or incomplete, because using it does not give me exactly what you show should.

    I've had to tweak some of the indices you use in the slices , as it looks like your input file contains a few more (or fewer) characters than you show in the example, perhaps some leading space. In any case, from the code that I give you, it should not be difficult to adapt it to your real case.

    The idea is the following:

    • The main program uses a loop in which in each iteration it reads 6 lines from the file, and extracts from the last read line a value N, which it uses to read the next N lines as well.

      To do this I make a loop for linea in fichero, but inside the loop I make it next(fichero)to read one more line each time I need it. That's why each iteration of the loop ends up reading 6+N lines.

    • The first 6 lines are saved in one list, the next N in another.

    • These two lists are passed to a function, which is the one that does the "dirty work" of extracting from each of those lines the fields that interest you, and using them to compose with them N lines in the output

    The use of the loop, the lists and the function greatly simplifies the code avoiding all the repetitions.

    It looks like this:

    def procesar(l, extra):
  """Funcion que recibe las 6 primeras líneas del grupo en la lista l
  y las N lineas siguientes en la lista extra, y que extrae de estas
  lineas la información relevante para componer la salida"""

  datos = []                       # Lista con los campos a mostrar en una línea
  datos.append(l[0][1:13].replace(" ", ""))  # A213992
  datos.append(l[0][31:40])                  # fecha
  datos.append(l[1][341:352])                # 070100
  datos.append(l[1][353:355])                # ??
  datos.append(l[1][15:49].rstrip())         # Nombre 1...
  datos.append("")                           # A sustituir en cada linea
  
  for n in extra:
    datos[-1] = n[4:12].strip()  # Sustituimos el último campo
    print(",".join(datos))       # imprimimos la línea resultante


# PROGRAMA "PRINCIPAL"

with open("tu-fichero.txt") as f:
  # Aparentemente iteramos por las líneas del fichero, pero en realidad
  # cada iteración de este bucle es por un bloque de 6+N lineas
  for line in f:
    l = [line]                            # guardar primera linea del bloque
    l.extend(next(f) for i in range(5))   # leer y guardar las 5 líneas siguientes
    numero = int(l[5])                    # Extraer N de la última línea leida
    extra = [next(f) for i in range(numero)] # leer y guardar las N lineas siguientes

    # Pasar las líneas leidas a la función que las procesa
    procesar(l, extra)

    And what I get (it is not exactly the same as what you put, because I am afraid as I said before that my input file is not exactly the same as yours) is the following:

    A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,475
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,941
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,190
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,192
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,412
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,4811
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,865
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,867
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,902
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,8298
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,546
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,711
A213992,5/01/2021,070100     ,  ,Nombre 1                     ","*,120
A213993,5/01/2021,           ,,",Nombre 2                   ","*,475
A213993,5/01/2021,           ,,",Nombre 2                   ","*,653
A213993,5/01/2021,           ,,",Nombre 2                   ","*,746
A213993,5/01/2021,           ,,",Nombre 2                   ","*,133
A213993,5/01/2021,           ,,",Nombre 2                   ","*,192
A213993,5/01/2021,           ,,",Nombre 2                   ","*,362
A213993,5/01/2021,           ,,",Nombre 2                   ","*,412
A213993,5/01/2021,           ,,",Nombre 2                   ","*,4811
A213993,5/01/2021,           ,,",Nombre 2                   ","*,546
A213993,5/01/2021,           ,,",Nombre 2                   ","*,902
A213993,5/01/2021,           ,,",Nombre 2                   ","*,948
A213993,5/01/2021,           ,,",Nombre 2                   ","*,120
A214012,4/01/2021,           , ",Nombre 3                   ","*,475
A214012,4/01/2021,           , ",Nombre 3                   ","*,192
A214012,4/01/2021,           , ",Nombre 3                   ","*,297
A214012,4/01/2021,           , ",Nombre 3                   ","*,412
A214012,4/01/2021,           , ",Nombre 3                   ","*,4811
A214012,4/01/2021,           , ",Nombre 3                   ","*,546
A214012,4/01/2021,           , ",Nombre 3                   ","*,865
A214012,4/01/2021,           , ",Nombre 3                   ","*,866
A214012,4/01/2021,           , ",Nombre 3                   ","*,867
A214012,4/01/2021,           , ",Nombre 3                   ","*,500
A214012,4/01/2021,           , ",Nombre 3                   ","*,8298
A214013,4/01/2021,           ,  ,Nombre 4                  ","*,412
A214013,4/01/2021,           ,  ,Nombre 4                  ","*,500
    • 0