How to write a Python for loop to write data to a CSV file?

A for loop is a programming construct that allows you to repeat a set of instructions a set number of times. In Python, a for loop looks like this:

for i in range(1, 10):

This for loop will execute the instructions inside the parentheses once for each number from 1 to 10.

CSV stands for ‘Comma-Separated Values‘. It denotes that the data (values) in a CSV file are separated by a delimiter i.e., comma. A CSV file stores data in tabular format with an extension of. .csv. CSV files are commonly used with Google spreadsheets or Microsoft Excel sheets. A CSV file contains a number of records with data distributed across rows and columns. In this article, we will use Python to visualize data from a CSV file.

To extract data from a CSV file, the CSV module must be imported into our program as shown below.:

import csv

with open('file.csv') as File:  
    Line_reader = csv.reader(File) 

Here, csv.After importing the CSV library, the reader() function is used to read the program.

Example 1: Using a bar plot to visualize the column of different people.

The CSV file below contains various person names, genders, and ages saved as 'biostats.'.csv’:

The approach of the program:

1. Import the necessary libraries, including the matplotlib library for visualization and the CSV library for reading CSV files.
2. Open the file with the open() function from the CSV library in 'r' mode (read-only) and read the file with csv.reader( ) function.
3. Using a for loop, read each line of the file.
4. Add necessary columns to a list.
5. After reading the entire CSV file, plot the necessary data as the X and Y axes.
6. In this example, we plot names as the X-axis and ages as the Y-axis.

Below is the implementation:

Python3

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

Output :

Example 2: Weather Report Visualization on Different Dates" through-line plot.

Temperature (°C) on various dates is saved in a CSV file as 'Weatherdata.'.csv’. These two rows, 'Dates' and 'Temperature(°C),' serve as the X and Y axes for displaying weather reports.

In this case,. Here we will check

• Python saves a string to a file
• Python saves a string to a file with newline
• Python saves a string to a file overwrite
• Python saves a string to a file without newline
• Python saves a string to a file append
• Python saves a string to a csv file.
• Python creates a csv file with a single row.
• Python for loop write to file
• Python saves a binary string to a file.
• Python string concatenation to file
• Python saves a string as utf-8 to a file.
• Python saves a string to a csv file.s without quotes

Python will save a string to a file.

Let us now look at how to write a string to a file in Python.

In this example, I used textfile = open("filename").to open the file (txt, mode) and "w" mode to write a file; other file modes include:

• r – read mode.
• a – append mode.
• w – writing mode.
• r - read and write modes.
• Here, a =textfile.write('string') is used to create a new file and write a string in it. I've named the file "example.".txt” textfile.The close() function is used to close the file.

Example:

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

The output in the images below shows a string in a file.

You might also be interested in Draw colored filled shapes in Python Turtle and How to Make a Snake Game in Python Using Turtle.

Python saves a string to a file with newline

Now we'll look at how to write a string to a file in Python using the newline character "n.".

In this case, I used open("filename").to open the file (txt, mode). And then call file.To write the string in the newly created file, use write('stringn').

And then I used "n "which produces a linebreak in the output and causes the output maker to move to the next line, and then I used the file.close() to close the file.

Example;

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

Below images shows the output:

We can see that the two strings are in different lines here.

Python will save a string to a file. overwrite

In this section, we will look at how to overwrite a string in a file in Python.

I used file = open("file") in this example.txt" mode) to access the file.

Then I took a string variable and changed it to fruits = ("mango is yellow").

Then used file.writelines(fruits) to save a string sequence to a file and file.close() to close the file.

Example:

file = open("example.txt", "w") 
fruits = ("mango is yellow") 
file.writelines(fruits) 
file.close() 

 

Below example shows the output:

In this example, I used "w" mode to add a new string to an already open file.

Example:

file = open("example.txt", "w") 
file.write("vegetables \n") 
file.close() 

Below example shows the output:

In this example,I used file.To overwrite the string, use the read() method.and file.close() to close the file.

Example:

file = open("example.txt", "r") 
print("Output of Readlines after writing") 
print(file.read()) 
print() 
file.close()

Below example shows the output:

This is the final code used to replace a string.

file = open("example.txt", "w") 
fruits = ("mango is yellow") 
file.writelines(fruits) 
file.close() 

file = open("example.txt", "w") 
file.write("vegetables \n") 
file.close()

file = open("example.txt", "r") 
print("Output of Readlines after writing") 
print(file.read()) 
print() 
file.close()

Python saves a string to a file append

Let us now look at how to append a string to a file in Python.

append means to add something to the end of an existing written document.

In this example, "and green" is appended to an existing string, resulting in the final string.

File = open("example") is used to append mode "a".txt”, “a”)), file.The appended string is read using read().

Example:

file = open("example.txt", "w") 
fruit = ("mangoes are yellow")
file.writelines(fruit) 
file.close() 
   
file = open("example.txt", "a")  
file.write(" and green \n") 
file.close() 
   
file = open("example.txt", "r") 
print("Output of Readlines after appending") 
print(file.read()) 
print() 
file.close()

Below image shows the output:

Python saves a string to a file without newline

Now we'll look at how to write a string to a file in Python without using a newline.

In this case, I used "r" instead of "n."

file = open("hello.txt", "w")
file.write('Hello all'"\r")
file.write('welcome to pythonguides')
file.close

Below image shows the output:

Python saves a string to a csv file.

Let's take a look at how to write a string in a csv file in Python.

CSV stands for comma separated value file. It is a simple file format that stores data in tabular form. such as excel sheet, database. The csv file should have .csv an extension.

Example:

In this example, I've used a list of strings to represent fruits.:

fruits = ['apple','cherry','orange','pineapple','strawberry']

Then I have used open(“filename.to open the file (csv, mode). dialect='excel' is used to define the excel format, which includes a set of parameters. writerow(item) is a method for writing a data row to the specified file.

Example:

textfile = open("example.txt", "w")
a = textfile.write('pythonguides')
textfile.close()

Below image shows the output:

All of the strings in this output are separated by commas.

Python creates a csv file with a single row.

Here's how to get a single row from a csv file. In this example, I've added the csv module file = open("filename").csv”,mode) csv.The writer() method creates a write object, and the writerow(item) function writes a single row in a csv file.

Example:

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

Below image shows the output:

Python for loop write to file

In this section, we will look at how to create a file for loop in Python.

A for loop is used to iterate over a sequence, but range function() can also be used. By default, the rangefunction returns a sequence of numbers beginning with 0 and increasing by one.

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

Below image shows the output:

Python saves a binary string to a file.

Let us now look at how to convert a binary string to a file.

I used file = open(filename) in this example.txt, mode) to open a file and 'w b'mode to write a file in binary format.

Assigned a binarystring of "01100011 01100011 01100001" and binaryvalues of "01100011 01100011 01100001".split() is used to split a string based on whitespace.

an_integer = int(binaryvalue, 2) This function is used to convert base2 decimal integers to integers.

ascii_character = chr(an_integer) and it is used to convert to ASCII character ascii_string += ascii_character this is used to append a character to string print(ascii_string)used to print a string, file.close() to close the file.

Example:

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

The image below shows the output, which includes the converted string.

Python string concatenation to file

In this section, we will look at how to create a file in Python to concatenate a string. Concatenation is the joining of two character strings end to end; for example, "football" is the concatenation of "foot" and "ball."

Example:

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

In this example, I used file = open('filename').txt''mode') to open the file, str1="foot" and str2="ball", print("".To join two strings, use join([str1, str2]). .str3 = ” “.join([str1, str2]) joins two strings separated by a space, then writes the concatenated string to the file file.write(str3) is used,file.close() to close the file.

Below image shows the output:

Python saves a string as utf-8 to a file.

utf-8- Unicode transformation format; it is a Unicode encoding system that is commonly used to encode email and webpages.

In this section, we'll look at how to save a string to a file in Python using the utf-8 encoding.

Example:

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

In this case, I used file = open('q').txt','mode)opens the file,'w b'mode only writes in binary format.

utf8 = “python, guides!”.encode() ,call string.encode() to encode the string to utf-8 bytes, followed by bytes.decode() is used to convert utf-8 encoded bytes to unicode strings.

file.write(utf8) to save an encoded value to a file .To convert a string to a byte, use str(b'abc','utf-8′) and to convert a byte to a string, use arr = bytes(b, 'utf-8') and file.write(arr) to save the decoded value to a file, and finally file.close() to close the file.

The image below depicts both the encoded and decoded values. .

Below image shows the output:

Python saves a string to a csv file.s without quotes

We can now see how to write a csv file in Python without quotes.

In this example, I imported the CSV module and used f= open("filename") to open a file.csv”, “mode”) and csv. writer () is used to insert data into a CSV file. Because we need to write a string to a CSV file without quotes, I used QUOTE_NONE to obtain a file without quotes.

Write all of the elements in rows.writerow() is used.

Example:

file = open("example.txt", "w")
file.write('Hello all! \nwelcome to pythonguides')
file.close

Below image shows the output:

You might be interested in the Python tutorials listed below.:

• Priority queue in Python
• Examples of Python epoch to DateTime
• Examples of Python variables written to files
• In Python, how do you convert a String to a DateTime?
• Escape sequence in Python
• Python list comprehension lambda
• Python Threading and Multithreading
• Converting Python degrees to radians
• Python Comparison Operators
• Python namespace tutorial
• Python Tkinter Frame
• Converting a Python string to a byte array with Examples
• Python read a binary file
• How to Convert a Python Array to a CSV File
• Example of Python reading a file line by line

This tutorial demonstrated how to:

• Python saves a string to a file
• Python saves a string to a file with newline
• Python saves a string to a file overwrite
• Python saves a string to a file without newline
• Python saves a string to a file append
• Python saves a string to a csv file.
• Python creates a csv file with a single row.
• Python for loop write to file
• Python string concatenation to file
• Python saves a string as utf-8 to a file.
• Python saves a string to a csv file.s without quotes

Bijay Kumar

Python is one of the most widely used programming languages in the United States of America. I have extensive experience working with Python libraries such as Tkinter, Pandas, NumPy, Turtle, Django, Matplotlib, Tensorflow, Scipy, Scikit-Learn, and others. I have worked with clients from the United States, Canada, the United Kingdom, Australia, and New Zealand. Check out my profile.

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