Nucleotide Count 筆記

[hic003cih]

您可以通過將字符串轉換為[] rune而不是使用strings.Split來將其拆分為單個字符。這也將消除大量的字符串轉換。 You can split a string into individual characters by casting it to []rune instead of using strings.Split. This will also do away with a lot of your string casts. 您可以檢查像這樣的映射中是否已經存在鍵，其中m是已經定義的映射： You can check if a key already exists in a map like this, where m is an already defined map:

if value, ok := m[<some key>]; ok {
    // do something knowing that <some key> does exist in the map.
}

在此示例中，ok是一個布爾值，指示在映射中是否存在。您可以將其使用，或者將其邏輯取反，再結合DNA序列的符文 In this example, ok is a boolean that indicates whether exists in the map. You can use this, or rather the logical negation of this, combined with the runes of the DNA sequence 安全地凋謝符文是有效的核苷酸，如果是，請在圖中增加其數量。您應該能夠在for循環中分4行執行此操作，包括錯誤檢查。 to safely tell wither a rune is a valid nucleotide, and if so, increment its count in the map. You should be able to do this in 4 lines, including error checking, inside the for loop.

[hic003cih]

原版

package dna

import (
    "errors"
    "strings"
)

// Histogram is a mapping from nucleotide to its count in given DNA.
// Choose a suitable data type.
type Histogram map[rune]uint

// DNA is a list of nucleotides. Choose a suitable data type.
type DNA string

// Counts generates a histogram of valid nucleotides in the given DNA.
// Returns an error if d contains an invalid nucleotide.
///
// Counts is a method on the DNA type. A method is a function with a special receiver argument.
// The receiver appears in its own argument list between the func keyword and the method name.
// Here, the Counts method has a receiver of type DNA named d.
func (d DNA) Counts() (Histogram, error) {
    d = DNA(strings.ToUpper(string(d)))
    h := Histogram{'A': 0, 'C': 0, 'G': 0, 'T': 0}
    for _, value := range strings.Split(string(d), "") {
        switch value {
        case string('A'):
            h['A']++
        case string('C'):
            h['C']++
        case string('G'):
            h['G']++
        case string('T'):
            h['T']++
        default:
            return h, errors.New("the string is not nucleotides")
        }
    }
    return h, nil

}

[hic003cih]

改進版

package dna

import (
    "fmt"
    "strings"
)

// Histogram is a mapping from nucleotide to its count in given DNA.
// Choose a suitable data type.
type Histogram map[rune]uint

// DNA is a list of nucleotides. Choose a suitable data type.
type DNA string

// Counts generates a histogram of valid nucleotides in the given DNA.
// Returns an error if d contains an invalid nucleotide.
///
// Counts is a method on the DNA type. A method is a function with a special receiver argument.
// The receiver appears in its own argument list between the func keyword and the method name.
// Here, the Counts method has a receiver of type DNA named d.
func (d DNA) Counts() (Histogram, error) {
    //d = DNA([]rune(strings.ToUpper(string(d))))
    var h = Histogram{
        'A': 0,
        'C': 0,
        'G': 0,
        'T': 0,
    }
    m := []rune(strings.ToUpper(string(d)))
    for _, nucleotide := range m {

        if _, ok := h[nucleotide]; !ok {
            return nil, fmt.Errorf("error")
        }

        h[nucleotide]++

    }
    return h, nil

}