从txt文件的不同行中读取特定编号，并将其添加到txt中每个行块的末尾

Question

I am realy new with python and already solved many of my problems searching and reading this site. But now the time had come for me to ask...

---

I have a txt file with the below structure:

SETUP

    STN_NO  419430403
    STN_ID  "S1"
    INST_HT 1.545000;
END SETUP
SLOPE (TgtNo, TgtID, CfgNo, Hz, Vz, SDist, RefHt, Date, Ppm, ApplType, Flags)
    419430405,  "S2",   1,  0.000000,   98.799682,  12.056200,  1.700000,   18-10-2012/10:06:08.0,  0.000000,   107,    00000000;
    419430407,  "1",    1,  0.000052,   98.799806,  12.056800,  1.700000,   18-10-2012/10:06:16.0,  0.000000,   107,    00000000;
    419430409,  "2",    2,  78.734236,  99.822405,  17.919000,  0.000000,   18-10-2012/10:09:50.0,  0.000000,   107,    00000000;
    419430410,  "3",    2,  78.861726,  108.352791, 17.213700,  0.000000,   18-10-2012/10:10:10.0,  0.000000,   107,    00000000;
END SLOPE

SETUP
    STN_NO  419430459
    STN_ID  "1"
    INST_HT 1.335000;
END SETUP
SLOPE (TgtNo, TgtID, CfgNo, Hz, Vz, SDist, RefHt, Date, Ppm, ApplType, Flags)
    419430462,  "S1",   5,  122.545107, 99.563594,  12.056300,  1.700000,   18-10-2012/11:04:36.0,  0.000000,   107,    00000000;
    419430464,  "50",   5,  200.000125, 99.563463,  12.058800,  1.700000,   18-10-2012/11:04:44.0,  0.000000,   107,    00000000;
    419430466,  "51",   6,  60.723043,  95.842462,  8.607300,   0.000000,   18-10-2012/11:06:36.0,  0.000000,   107,    00000000;
    419430467,  "52",   6,  99.683958,  95.664912,  7.581100,   0.000000,   18-10-2012/11:08:15.0,  0.000000,   107,    00000000;
    419430468,  "53",   6,  101.389131, 87.173327,  7.853000,   0.000000,   18-10-2012/11:08:51.0,  0.000000,   107,    00000000;
END SLOPE
END THEODOLITE

---

The problem is that i want to add to the end of each line the proper INST_HT value (meaning 1.545000 in the first block of data between SLOPE and END SLOPE and 1.335000 in the second, etc).

The goal is to create a proper csv file containing the numeric data of TgtID, Hz, Vz, SDist, RefHt columns (already done that) and INST_HT (missed that one!!!).

Until now the only think that i have done is creating a list with all the INST_HT values from beggining to the end of the file.

Any ideas?

Answer 1

This should work for the problem you described:

INST_HT = [1.545000,
           1.335000]
lines = open('tmp.txt')
out = open('tmp2.txt', 'w')
i = -1
while True:
    try:
        line = lines.next()
    except StopIteration:
        break
    if 'slope' in line.lower():
        i += 1
        out.write(line)
        while True:
            line = lines.next()
            if 'end slope' in line.lower():
                out.write(line)
                break
            else:
                out.write('    ' + line.strip()[:-1] + ', ' + str(INST_HT[i]) + ';\n')
    else:
        out.write(line)
out.close()

Answer 2

Think about the problem this way: You want to go line by line, and do different things with each line.

last_inst_ht = None
in_slope = False
with open('infile.txt') as infile, open('outfile.txt') as outfile:
    for line in infile:
        if line.startswith('SLOPE'):
            bits = line.split(')')
            line = bits[0] + ', INST_HT' + bits[1]
            in_slope = True
        elif line.startswith('END SLOPE'):
            in_slope = False
        elif in_slope:
            bits = line.split(';')
            line = bits[0] + ', ' + last_inst_ht + bits[1]
        elif line.strip().startwith('INST_HT'):
            last_inst_ht = line.strip().split()[-1][:-1]
        outfile.write(line)

You can make this a bit more robust by keeping track of more state information. If you get an INST_HT outside of a SETUP , maybe you should print a warning or an error. Or if you get two SETUP blocks, or none, before a SLOPE . Or if you get a SETUP without an INST_HT in it. And so on.

Also, the way I'm parsing the lines isn't exactly robust. For example, if you could have a ; in one of your fields, we'd instead the last_inst_ht into the middle of that field instead of at the end. But I wanted to keep things simple and brief in hopes that you'd understand the logic instead of just copying it blindly, so you can expand and debug it yourself in the future.