Nishant Tyagi
In this article you will learn Python Built-in functions, libraries and modules.
Python has many inbuilt modules and packages. Today we sill discuss them all.
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- Introduction to Programming – Day1
- Introduction to Algorithms – Day 2
- Python operators and variables – Day 3
- Python Control Structures – Day 4
- Functions in Python – Day 5 of Python Series
- How to setup Eclipse IDE for Python? – 6th Day of Python Series
- Collection Data types in Python – 7th Day of Python Series
- Python Debugging and Testing –Python Series-8th day
1.Random Library function in python
Random library in python is very useful. This module helps in generating random numbers.
The code given below generates a random number between x and y-1 (both inclusive) using the randrange function of the random module.
import random
x=10
y=50
print(random.randrange(x,y)) Output will be different in each run.
Methods in random module.
| Method | Description |
| seed() | Initialize the random number generator |
| getstate() | Returns the current internal state of the random number generator |
| setstate() | Restores the internal state of the random number generator |
| getrandbits() | Returns a number representing the random bits |
| randrange() | Returns a random number between the given range |
| randint() | Returns a random number between the given range |
| choice() | Returns a random element from the given sequence |
| choices() | Returns a list with a random selection from the given sequence |
| shuffle() | Takes a sequence and returns the sequence in a random order |
| sample() | Returns a given sample of a sequence |
| random() | Returns a random float number between 0 and 1 |
| uniform() | Returns a random float number between two given parameters |
| triangular() | Returns a random float number between two given parameters, you can also set a mode parameter to specify the midpoint between the two other parameters |
| betavariate() | Returns a random float number between 0 and 1 based on the Beta distribution (used in statistics) |
| expovariate() | Returns a random float number between 0 and 1, or between 0 and -1 if the parameter is negative, based on the Exponential distribution (used in statistics) |
| gammavariate() | Returns a random float number between 0 and 1 based on the Gamma distribution (used in statistics) |
| gauss() | Returns a random float number between 0 and 1 based on the Gaussian distribution (used in probability theories) |
| lognormvariate() | Returns a random float number between 0 and 1 based on a log-normal distribution (used in probability theories) |
| normalvariate() | Returns a random float number between 0 and 1 based on the normal distribution (used in probability theories) |
| vonmisesvariate() | Returns a random float number between 0 and 1 based on the von Mises distribution (used in directional statistics) |
| paretovariate() | Returns a random float number between 0 and 1 based on the Pareto distribution (used in probability theories) |
| weibullvariate() | Returns a random float number between 0 and 1 based on the Weibull distribution (used in statistics)Please do not confuse we will talk about these all later. |
Python math module
math is another useful module in Python. Once you have imported the math module, you can use some of the below functions:
| Function | Explanation |
| math.ceil(x) | Smallest integer greater than or equal to x |
| math.floor(x) | Largest integer smaller than or equal to x |
| math.factorial(x) | Factorial of x |
| math.fabs(x) | Gives absolute value of x |
Try the code:
import math
num1=234.01
num2=6
num3=-27.01
print("The smallest integer greater than or equal to num1,",num1,":",math.ceil(num1))
print("The largest integer smaller than or equal to num1,",num1,":",math.floor(num1))
print("The factorial of num2,",num2,":", math.factorial(num2))
print("The absolute value of num3",num3,":",math.fabs(num3))String Functions in python
String data type in Python has many inbuilt functions which make it easier to work with strings.
Consider the string, name="Raghav".
| Function | Output | Explanation |
| name.count(“a”) | 2 | Returns the count of a given set of characters. Returns 0 if not found |
| name.replace(“a”,”A”) | RAghAv | Returns a new string by replacing a set of characters with another set of characters. It does not modify the original string |
| name.find(“a”) | 1 | Returns the first index position of a given set of characters |
| name.startswith(“Ra”) | True | Checks if a string starts with a specific set of characters, returns true or false accordingly. |
| name.endswith(“ha”) | False | Checks if a string ends with a specific set of characters, returns true or false accordingly. |
| name.isdigit() | False | Checks if all the characters in the string are numbers, returns true or false accordingly. |
| name.upper() | RAGHAV | Converts the lowercase letters in string to uppercase |
| name.lower() | raghav | Converts the uppercase letters in string to lowercase |
| name.split(“a”) | [‘R’, ‘gh’, ‘v’] | Splits string according to delimiter and returns the list of substring. Space is considered as the default delimiter. |
List Functions in Python
List data type in Python also have many inbuilt functions.
| Function | Output | Explanation |
| num_list.append(60) | [10,20,30,40,50,60] | Adds an element to end of list |
| num_list.index(10) | 0 | Returns the index position of the element.In case of multiple occurrence of the element, returns the index of the first occurrence.Throws ValueError, if the element is not found |
| num_list.insert(3,60) | [10,20,30,60,40,50] | Inserts an element at a given position |
| num_list.pop(3) | 40 | Removes and returns the element at given index position from the list |
| num_list.remove(30) | [10,20,40,50] | Removes the first occurring element whose value is 30 |
| num_list.sort() | [10,20,30,40,50] | Sorts the list in ascending order |
| num_list.reverse() | [50,40,30,20,10] | Reverses the list |
Dictionary function in python
Dictionary in Python also have many inbuilt functions.
Consider a dictionary:
crew_details={
"Pilot":"Kumar",
"Co-pilot":"Raghav",
"Head-Strewardess":"Malini",
"Stewardess":"Mala"
}| Function | Output | Explanation |
| crew_details.get(“Pilot”) | Kumar | Returns the value for given key. If the given key is not found, returns None |
| crew_details.update({“Flight Attendant”:”Jane”, “Co-pilot”:”Henry”}) | No output, dictionary will be updated | Updates the dictionary with the given key-value pairs. If a key-value pair is already existing, it will be overwritten, otherwise it will be added to the dictionary |
Python Date and Time module
Python has inbuilt modules called time and datetime. They are very helpful in finding details of time.
| Function | Explanation |
| time.gmtime() | Returns the current GM time |
| time.localtime() | Returns the current time based on the current locality |
| time.strftime(t,format) | Converts t to a string as specified by the format argument and returns it.Where t is the time returned by time.gmtime() or time.localtime(). It is optional, default value is current time as returned by time.localtime() |
| datetime.datetime.strptime (date_string, format) | Converts a date string in the specified format to a datetime value and returns it |
| datetime.date.today() | Returns the current local date |
we hope you liked this article. In this article, we discussed the various functions and libraries in python. If you have any queries or confusion feel free to contact us anytime.
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Start learning Python from scratch for Free.
- Introduction to Programming – Day1
- Introduction to Algorithms – Day 2
- Python operators and variables – Day 3
- Python Control Structures – Day 4
- Functions in Python – Day 5 of Python Series
- How to setup Eclipse IDE for Python? – 6th Day of Python Series
- Collection Data types in Python – 7th Day of Python Series
- Python Debugging and Testing –Python Series-8th day
End of python Built-in function article.
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