Related Articles
How to find the first Monday of a given month using NumPy?
• Last Updated : 02 Dec, 2020

To find the first Monday of a given month, we are going to use the numpy module i.e the numpy.busday_offset() method in numpy module.

Parameters:

date: The array of dates to process.

offsets: The array of offsets, which is broadcast with dates.

roll:It takes the below values:

• raise means to raise an exception for an invalid day.
• nat means to return a NaT (not-a-time) for an invalid day.
• forward and following mean to take the first valid day later in time.
• backward and preceding mean to take the first valid day earlier in time.
• modifiedfollowing means to take the first valid day later in time unless it is across a Month boundary, in which case to take the first valid day earlier in time.
• modifiedpreceding means to take the first valid day earlier in time unless it is across a Month boundary, in which case to take the first valid day later in time.

weekmask: array indicating which of Monday through Sunday are valid days.

Returns (outarray of datetime64): An array with a shape from broadcasting dates and offsets together, containing the dates with offsets applied.

#### Below are some programs which use numpy.busday_offset() method to get first Monday of a month:

Example #1:

In this example, we will find the first Monday of the month of May 2017.

## Python3

 `# import module``import` `numpy`` ` `# input year and month``yearMonth ``=` `'2017-05'`` ` `# getting date of first monday``date ``=` `numpy.busday_offset(yearMonth, ``0``, ``                           ``roll``=``'forward'``, ``                           ``weekmask``=``'Mon'``)`` ` `# display date``print``(date)`

Output:

`2017-05-01`

Example #2:

Here, we will find the first Monday of the month of February 2001.

## Python3

 `# import module``import` `numpy`` ` `# input year and month``yearMonth ``=` `'2001-02'`` ` `# getting date of first monday``date ``=` `numpy.busday_offset(yearMonth, ``0``,``                           ``roll``=``'forward'``,``                           ``weekmask``=``'Mon'``)`` ` `# display date``print``(date)`

Output:

`2001-02-05`

Example #3:

Here, we will find the first Monday of the month of November 2020.

## Python3

 `# import module``import` `numpy`` ` `# input year and month``yearMonth ``=` `'2020-11'`` ` `# getting date of first monday``date ``=` `numpy.busday_offset(yearMonth, ``0``,``                           ``roll``=``'forward'``,``                           ``weekmask``=``'Mon'``)`` ` `# display date``print``(date)`

Output:

`2001-11-02`

Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up