I want to delete rows from line 2 to a specific numbers in CSV file, but it deletes all from the file

Question

Currently, It is deleting everything in CSV, also How can I make a default number so, It will delete from line 2nd to a specific row.

This is what I'm doing

import csv

user_input = input("Please enter a row name to be deleted.")
read = open('color.csv', 'rb')
write = open('color.csv', 'wb')
writer = csv.writer(write)

for row in csv.reader(user_input):

    if row == input:
        writer.writerow(row)
        read.close()
        write.close()
        
print('Used colors names deleted')

Answer 1

The main reason is deletes all from the file is that you open the same file in read mode and write mode. Opening an existing file in write mode will clear it completely.

Relevant documentation: here

open(filename, mode):
The first argument is a string containing the filename. The second argument is another string containing a few characters describing the way in which the file will be used. mode can be 'r' when the file will only be read, 'w' for only writing (an existing file with the same name will be erased), [...]

(emphasis mine)

---

Your code has plenty of other problems:

• input() stored in input - overwriting the built in (you edited that, great :o) )
• using binary mode on file open for textfiles
• using the csv.reader(...) on a string - not the filehandle
• not using newline="" on file open for csv module
• not writing all data to the new file
• comparing the csv row (a list) to user_input which is a string
• trying to open the same file for reading and writing and doing both
• not using context handlers for file operations

To fix it, open a different file for the output, read the input-file, compare the first value of your row to the userinput and skip writing this line if it matches

See other related posts to line deletion in csv at the end - your problem here is not a dupe because those happen to not overwrite the file at hand using the same names.

Create csv demo file:

with open ("color.csv","w") as f:
   for color in ['blue', 'crash', 'pink', 'gold', 'silver']:
       f.write(f"{color},some other,tabulars in the,csv\n")

Process file:

"""This code deletes rows with a given 'color' in column 0"""
import csv

color_to_delete = "pink" # input("Please enter a row name to be deleted.")
# not binaryy - it is a CSV with is TEXT - and you need to supply newline=""
with open('color.csv', newline="") as r, open("2ndColor.csv","w", newline="") as w:  

    writeme = csv.writer(w)
    for row in csv.reader(r): # why input? you need the file handle
        if row[0] == color_to_delete:
            continue # skip this row
        writeme.writerow(row)

print("# before:")
print(open("color.csv").read())
print("\n# after:\n" + open("2ndColor.csv").read())

Output:

# before:
blue,some other,tabulars in the,csv
crash,some other,tabulars in the,csv
pink,some other,tabulars in the,csv
gold,some other,tabulars in the,csv
silver,some other,tabulars in the,csv


# after:
blue,some other,tabulars in the,csv
crash,some other,tabulars in the,csv
gold,some other,tabulars in the,csv
silver,some other,tabulars in the,csv

---

To remove multiple lines after the inputtedcolor you add:

"""This code deletes rows with a given 'color' in column 0 and the following
'lines_to_deete' rows""" 

color_to_delete = "pink" # input("Please enter a row name to be deleted.")
lines_to_delete = 1  # will delete the pink line and 1 more
lc = 0

with open('color.csv', newline="") as r, open("2ndColor.csv","w", newline="") as w:      
    writeme = csv.writer(w)
    for row in csv.reader(r): # why input? you need the file handle
        if row[0] == color_to_delete:
            lc = lines_to_delete 
            continue # skip this row
        elif lc:
            lc -= 1
            continue
        writeme.writerow(row)

to get an output of:

after:
blue,some other,tabulars in the,csv
crash,some other,tabulars in the,csv
silver,some other,tabulars in the,csv

---

To skip certain line ranges, you can do:

import csv

lines_to_skip = range(2,5) # 2,3,4

with open('color.csv', newline="") as r, open("2ndColor.csv","w", newline="") as w:      
    writeme = csv.writer(w)
    # enumerate the input and skip row if in range
    for line_num, row in enumerate(csv.reader(r)): # why input? you need the file handle
        if line_num in lines_to_skip:
            continue # skip this row

        writeme.writerow(row)

to get an output of:

after:
blue,some other,tabulars in the,csv
crash,some other,tabulars in the,csv

---

Explanation of the modes for file opening see Difference between modes a, a+, w, w+, and r+ in built-in open function?

Related posts:

• Deleting rows with Python in a CSV file
• Delete some rows of a CSV, in-place
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