Python updating a text file adding headers and their corresponding values

Question

I have a text file named headerValue.txt which contains the following data:-

Name   Age
sam    22
Bob    21

I am trying to write a python script that would add a new header called 'Eligibility'. It would read the lines from the text file and check if the age is more than 18, then it will print 'True' underneath 'Eligibility' header and also add one more header named 'Adult' and print a 'yes' underneath and 'no' if the age is less than 18.

Since in the text file the age of both is more than 18. The output will something be like:-

Name    Age    Eligibility    Adult
sam     22       True         yes
Bob     21       True         yes

code snippet:-

fo =open("headerValue.txt", "r")
data = fo.readlines()
for line in data:
    if "Age" in line:
        if int(Age) > 18:
            Eligibility = "True"
            Adult = "yes"

I am kinda stuck here since I am new to python. Any help how to update the text file and add headers with its values?Thanks

I think you wanted an update for the original file . — Juan Diego Godoy Robles
– Juan Diego Godoy Robles, Commented Jul 15, 2014 at 6:54

tktk · Accepted Answer · 2014-07-15 06:40:21Z

1

fo =open("headerValue.txt", "r")
data = [l.split() for l in fo.readlines()]
headers = data[0]
headers.extend(('Eligibility', 'Adult'))
ageind = headers.index('Age')
for line in data[1:]:
    if int(line[ageind]) > 18:
        line.extend(('True', 'yes'))
    else:
        line.extend(('False', 'no'))

The if in your code would only be true for the first line (not the one you're interested in). I replaced it with checking for the index of age. Also, usually variable names are not capitalized. Also, regarding data = [l.split() for l in fo.readlines()] - it looks like your file is space separated. If it's tab/comma separated you can split accordingly, but I suggest using csv.

edited Jul 15, 2014 at 6:40

answered Jul 15, 2014 at 6:33

tktk

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2 Comments

tktk Over a year ago

@klashxx Doesn't say so anywhere in his question.

Juan Diego Godoy Robles Over a year ago

Yes, he did: Any help how to update the text file and add headers with its values?

msvalkon · Accepted Answer · 2014-07-15 06:52:27Z

You're trying to check if the string "Age" exists in a line. It only exists on the first line. Then you try to convert a variable Age to an integer and see if it's larger than 18. I can't see that you've defined Age anywhere so I can't tell if this code runs.

It seems like you have a tab-delimited or a space-delimited file. It looks like a CSV-file so you might as well treat it as such. It's easier, because python provides a builtin csv module. In that module there's the csv.DictReader and csv.DictWriter objects which allow you to modify each line in the csv-file as a dictionary. In the below file, the csv.DictWriter gets default header names and the restval-parameter defines the default parameter for the fields. This simplifies the code as you can see below:

>>> with open("test.csv", "r") as inf, open("out.csv", "w") as outf:
...    in_reader = csv.DictReader(inf, delimiter=" ")
...    out_writer = csv.DictWriter(outf, delimiter=" ", fieldnames=['Name', 'Age', 'Eligibility', 'Adult'], restval=False)
...    out_writer.writeheader()
...    for line in in_reader:
...        if int(line['Age']) > 18:
...             line['Eligibility'] = True
...             line['Adult'] = True
...         out_writer.writerow(line)

Input file is test.csv:

msvalkon@lunkwill~$: cat test.csv
Name Age
sam 22
Bob 21
foo 5

Output in out.csv:

msvalkon@lunkwill~$: cat out.csv
Name Age Eligibility Adult
sam 22 True True
Bob 21 True True
foo 5 False False

Juan Diego Godoy Robles · Accepted Answer · 2014-07-15 06:45:12Z

0

This module is suited for you : https://docs.python.org/2/library/fileinput.html?highlight=fileinput#fileinput

For a infile edition you can use:

#!/usr/bin/python
import fileinput

cont = 0
for line in fileinput.input("./path/to/file", inplace=True):
    if not cont:
        name = "Name"
        age = "Age"
        Eligibility= "Eligibility"
        Adult = "Adult"
    else:
        name ,age = line.split()
        if int(age) > 18:
                Eligibility = "True"
                Adult = "yes"
    print "{0}\t{1}\t{2}\t{3}".format(name, age, Eligibility, Adult)
    cont += 1

This , will update your original file.

edited Jul 15, 2014 at 6:45

answered Jul 15, 2014 at 6:32

Juan Diego Godoy Robles

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