没有合适的资源?快使用搜索试试~ 我知道了~
首页Python实现生物信息学算法设计与实践指南
Python实现生物信息学算法设计与实践指南
需积分: 5 0 下载量 136 浏览量
更新于2024-06-20
收藏 6.7MB PDF 举报
"《生物信息学算法:Python设计与实现》是一本由Miguel Rocha和Pedro G. Ferreira合著的专业书籍,两位作者分别来自葡萄牙University of Minho和Ipatimup/i3S。本书隶属于学术出版社Academic Press,是Elsevier的一个分支,总部位于英国伦敦和美国的San Diego、Cambridge以及美国的Kidlington等地。该书出版于2018年,版权归属于Elsevier公司,所有复制或传播必须获得书面许可。 本书内容深入浅出,详细介绍了生物信息学算法的设计和Python语言的实现方法。生物信息学是研究生命科学中的数据处理、分析和解读的学科,它在基因组学、蛋白质组学、代谢组学等领域发挥着关键作用。通过学习本书,读者可以掌握如何利用Python这种强大的编程语言来解决生物信息学中的各种问题,如序列比对、基因功能预测、结构生物学分析等。 书中涵盖了丰富的实践案例和理论讲解,不仅包括基本概念的阐述,还涉及高级技术的探讨,帮助读者从入门到进阶,逐步提升在生物信息学领域的能力。此外,书中还强调了版权保护的重要性,并提供了关于Elsevier版权政策和如何获取许可的详细信息,确保读者在合法范围内进行学术活动。 《生物信息学算法:Python设计与实现》是一本既实用又全面的教材,对于生物信息学专业学生、研究人员和对这一领域感兴趣的开发者来说,都是宝贵的学习资源。通过学习这本书,读者不仅能掌握生物信息学的核心算法,还能提升计算机编程和数据处理技能,适应现代生命科学研究的需求。"
资源详情
资源推荐
10 Chapter 2
If a variable is no longer being used it can be removed by using the del clause.
>>> del x
2.2.3 Numerical and Logical Variables
Numeric variables can be either integer, floating point (real numbers), or complex numbers.
Boolean variables can have a True or False value and are a particular case of the integer
type, corresponding to 1 and 0, respectively.
# integer
>>> sequence_length = 320
# floating
>>> average_score = 23.145
# Boolean
>>> is_sequence = True
>>> contains_substring = False
Multiple variables can also be assigned with the same value in a single line:
>>>a=b=c=1
Multiple values can be assigned to different variables in a single instruction, in the order they
are declared. In this case, variables and values are separated by commas:
>>>a,b,c=1,2,3
Assignments using expressions in the right hand side are possible. In this case, the evaluation
of the expression follows the arithmetic precedence rules.
>>> a = 2∗(1+2)
Variable values can also be swapped in the same line.
>>> a,b,c = c,a,b
The following binary arithmetic operators can be applied to two numeric variables:
• + –sum;
• - – difference;
• * – multiplication;
An Introduction to the Python Language 11
Table 2.2: Mathematical and character functions.
Function Description
abs(x) absolute value of x
round(x, n) x rounded to a precision of n places
pow(x, y) x raised to power of y
ord(c ) ASCII numerical code for character c
chr(x) ASCII string (with a single character) for numerical code x
• / – division;
• ** – exponentiation;
• // – integer division; and,
• % – modulus operator (remainder of the integer division).
All the usual arithmetic priorities apply here as well. Some examples are shown in the follow-
ing code:
>>> x = 5
>>> y = 4
>>> x + y
9
>>> x ∗ y
20
>>> x / y
1
>>>x//y
1
>>> z = 25
>>> z % x
0
>>> z % y
1
>>> x ∗∗ y
625
Table 2.2 describes examples of mathematical functions and functions to convert between
numerical values and characters based on the ASCII code.
Examples of the use of these functions follow:
>>> abs(−3)
3
12 Chapter 2
>>> round (3.4)
3.0
>>> float(2)
2.0
>>> int(3.4)
3
>>> int(4.6)
4
>>> int (−2.3)
−2
>>> 0.00000000000001
1e−14
>>> 2.3e−3
0.0023
>>> chr (97)
’a’
>>> ord(’a’)
97
The package math includes a vast number of useful mathematical and scientific functions,
including trigonometric functions (sin, cos, tan), square root (sqrt), and others as factorial,
logarithm (log) and power function (exp), where exp(x) returns e
x
. By importing this pack-
age, these functions become available in the current working session.
With these capacities, the interactive environment of Python becomes a powerful scientific
calculator, as shown in the examples below:
>>> import math
>>> math .sqrt (4)
2.0
>>> math .sin (0.5)
0.479425538604203
>>> math.log(x)
1.6094379124341003
>>> math .pi
3.141592653589793
>>> math .tan (math. pi)
−1.2246467991473532 e−16
>>> math .e
2.718281828459045
An Introduction to the Python Language 13
>>> math .exp(1)
2.718281828459045
>>> math .log (math. e)
1.0
Notice in the previous examples that the constants pi and e are also available within the pack-
age.
When updating a variable x through an arithmetic operation that depends on the current state
of x, the assignment operator can be preceded by a mathematical operator, +=, -=, *=, /=, %=
or **=. As an example, the two following expressions are equivalent:
# equivalent statements
>>>a+=3
>>> a = a+3
Given two Boolean variables x and y, the logical operations and, or,andnot provide a logi-
cal result of True or False, returning respectively the logical conjunction, disjunction, and
negation.
2.2.4 Containers
2.2.4.1 Lists
Lists allow the storage and processing of sequences of values of different types. They can be
defined by square brackets enclosing a sequence of comma-separated values. The notation []
defines an empty list.
A list with the integer values from 1 to 5 and 7 can be declared as follows:
>>>x=[1,2,3,4,5,7]
Each of the values in a list can be accessed by an index that defines the position of the value
within the sequence. Indexes are integer values that range from 0 (first position) to the number
of elements on the list minus 1 (last position). To access the third element of the previously
defined list, we can use the syntax x[2]. Since lists are mutable objects, we can also directly
change their values, for instance with x[0]=−1, setting the first element to be −1.
By using negative indexes, the elements of the list can be accessed backwards, where x[−1]
corresponds to the last element of the list, i.e. 7, x[−2] to the second last element, and so on.
Elements can also be removed from lists with the del statement.
14 Chapter 2
>>>x=[1,2,3,4,5,7]
>>> del x [4]
>>> x
[1 , 2 , 3 , 4 , 7]
The list object can handle heterogeneous data. Thus, as the example below shows, a list may
contain data from different types including other lists.
>>> y = [1, 2, "A", "B",[4,"C"]]
The + operator can be used to concatenate (join) lists together:
>>> [1 ,2 ,3] + [4 ,5 ,6]
[1,2,3,4,5,6]
Slicing is a powerful mechanism to generate sub-lists, i.e. lists containing selected el-
ements that preserve their order from the original list. The general syntax for slicing is
list_name[startslice : endslice : step]. Note that a more compact syntax for slicing can be used
by omitting some arguments. In the case where it is possible to omit arguments, default values
are assumed. Also, the endslice is always one position after the last selected element.
Examples of slicing on lists follow below:
>>> x
[1 , 2 , 3 , 4 , 7]
# elements from index 1 to 2
>>> x[1:3]
[2 , 3]
# elements from index 0 to 2
>>> x [:3]
[1 , 2 , 3]
# elements from index 3 to end of list
>>> x [3:]
[4 , 7]
# all elements but the last element
>>> x[:−1]
[1 , 2 , 3 , 4]
# every two elements
>>> x[::2]
[1 , 3 , 7]
# skipping first and last elements
剩余394页未读,继续阅读
qq_24590525
- 粉丝: 1
- 资源: 129
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
最新资源
- zlib-1.2.12压缩包解析与技术要点
- 微信小程序滑动选项卡源码模版发布
- Unity虚拟人物唇同步插件Oculus Lipsync介绍
- Nginx 1.18.0版本WinSW自动安装与管理指南
- Java Swing和JDBC实现的ATM系统源码解析
- 掌握Spark Streaming与Maven集成的分布式大数据处理
- 深入学习推荐系统:教程、案例与项目实践
- Web开发者必备的取色工具软件介绍
- C语言实现李春葆数据结构实验程序
- 超市管理系统开发:asp+SQL Server 2005实战
- Redis伪集群搭建教程与实践
- 掌握网络活动细节:Wireshark v3.6.3网络嗅探工具详解
- 全面掌握美赛:建模、分析与编程实现教程
- Java图书馆系统完整项目源码及SQL文件解析
- PCtoLCD2002软件:高效图片和字符取模转换
- Java开发的体育赛事在线购票系统源码分析
资源上传下载、课程学习等过程中有任何疑问或建议,欢迎提出宝贵意见哦~我们会及时处理!
点击此处反馈
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功