Problem Formulation and Solution Overview
Over your career as a Python coder, you will encounter situations when a string needs to be output/displayed a specified number of times. The examples below offer you various ways to accomplish this task.
Method 1: Use print() and multiplication operator
This method uses Python’s built-in
print() statement combined with a
multiplication operator to output a string multiple times.
saying = 'Wash. Rinse. Repeat!\t' print(saying * 3)
Above declares the string ‘
Wash. Rinse. Repeat!‘ followed by a tab character, also known as an escape character (
\t). The results save to
saying.
Next, the
print() statement outputs the
saying three (3) times, with the escape character (
\t) between each
saying on the same line.
Method 2: Use a For Loop and range()
This method uses a
for loop with the
range() function to iterate and output a string a set number of times.
for i in range(3): print('I never want to grow up!')
Above instantiates a
For loop with the
range() function. This function accepts a start position (not required), a stop position (required) and a step (not required). The start position is always zero (
0) unless otherwise stated. The stop position is always stop-1.
The
print() statement outputs a line to the terminal, with each iteration as shown below.
Method 3: Use the
input() function
This method prompts the user to enter a specified number of times to repeat a string using the
int() and
input() functions.
num = int(input('Number of times to repeat a string? ')) print('Hello World!\n' * num)
Above, prompts the user to enter how many times a string will display. Their answer is converted to an integer (
int()) and saved to
num.
Next, the string ‘
Hello World‘ is output to the terminal. The newline character is appended (
\n) so the output displays on a new line each time.
For this example, the number three (3) was entered.
💡Note: The newline character (
\n) caused the last line (line 3) to have an additional blank line.
Method 4: Use itertools.repeat()
This method uses Python’s built-in library
itertools to call the
repeat() function, which repeats a number or a string a stated number of times.
import itertools print(list(itertools.repeat('HELP ME', 3)))
Above, imports the
itertools library.
Then, the
repeat() function is called and passed two (2) arguments: the string to repeat and the number of times to repeat. This is then converted to a
list and output to the terminal.
Method 5: Use a DataFrame
This method uses a DataFrame and an empty column to assign a default value.
The
Pandas library must be installed and imported to run this code error-free. Click here for installation instructions.
To follow along, click here to download the
finxters.csv file and move this file to the current working directory.
import pandas as pd df = pd.read_csv('finxters.csv', usecols=['FID', 'First_Name', 'Last_Name']) df['Award'] = 'TBD' df.to_csv('finxter1.csv') print(df.head(3))
Above, imports the
Pandas library to read in the CSV file and work with a DataFrame.
Then, only a few columns of
finters.csv are read into the DataFrame
df.
Next, the DataFrame
df is saved to a new CSV file,
finxters1.csv and placed in the current working directory.
Finally, the output is sent to the terminal. For this example, only three (3) rows are displayed.