05_自訂函數

--- tags: python --- # 05_自訂函數 * 除內建函數以外，也可以將常用的功能包成一個函數 ### 計算矩形面積 ```python def rect(width, height): ''' This function will return the area of an rectangel ''' area = width * height return area area = rect(2, 3) print(area) # 6 ``` ### 從指定區間中取得指定數量隨機數 ```python from random import choice # 參數可以做預設值 def get_rand(start=1, end=100, amount=4): ''' By default, this function will retrun four unique random numbers in a range from 1 to 100. ''' nums = [n for n in range(start, end +1)] result = [] for n in range(amount): rand = choice(nums) result.append(rand) nums.remove(rand) return result # 不加入參數arguments的情況下，函數也可以執行 get_rand() # [38, 95, 51, 72] 0到100中取4個不重複數字 ``` ### 自訂一個parse FASTA format的函數 ```python ''' The header/identifier of a sequence in a FASTA file usually starts with a ">". Subsequent lines are the actual sequence which may be a dna, rna, or protein sequence. ''' def fasta_parse(raw): raw = raw.split() name_list, seq_list = [], [] seq = '' for line in raw: if line.startswith('>'): # 第一個迴圈seq為空字串，不進行append if seq: seq_list.append(seq) seq = '' name_list.append(line.strip('>')) continue seq += line # 迴圈結束後的最後一組seq要再append進seq_list才完整 seq_list.append(seq) seqs = list(zip(name_list, seq_list)) return seqs raw = ''' >one ATCC TGAA >two CGAA CCGG >three ATCG GTTA ''' seqs = fasta_parse(raw) print(seqs) # [('one', 'ATCCTGAA'), ('two', 'CGAACCGG'), ('three', 'ATCGGTTA')] ``` > Written with [StackEdit](https://stackedit.io/).