In [1]:

    

"A"


    

    
Out[1]:





A

In [2]:

    

"ACGT"


    

    
Out[2]:





ACGT

In [3]:

    

st := "ACGT"


    

In [4]:

    

len(st)


    

    
Out[4]:





4

In [5]:

    

""


    

    
Out[5]:

In [6]:

    

len("")


    

    
Out[6]:





0

In [7]:

    

import "math/rand"
st = "ACGT"
string(st[rand.Intn(len(st))]) // generating a random nucleotide


    

    
Out[7]:





C

In [8]:

    

string(st[rand.Intn(len(st))]) // repeated invocations might yield different nucleotides


    

    
Out[8]:





T

In [9]:

    

string(st[rand.Intn(len(st))]) // repeated invocations might yield different nucleotides


    

    
Out[9]:





T

In [10]:

    

string(st[rand.Intn(len(st))]) // repeated invocations might yield different nucleotides


    

    
Out[10]:





T

In [11]:

    

string(st[rand.Intn(len(st))]) // repeated invocations might yield different nucleotides


    

    
Out[11]:





C

In [12]:

    

// make random nucleotide string by concatenating random nucleotides
import "bytes"
var b bytes.Buffer
for i := 0; i < 40; i++ {
    b.WriteByte(st[rand.Intn(len(st))])
}
st = b.String()
st


    

    
Out[12]:





GCAAAGTGCAGTCCGTGAGTTTAGTCATTCACTCGCGGTC

In [13]:

    

st[1:3] // substring, starting at position 1 and extending up to but not including position 3
// note that the first position is numbered 0


    

    
Out[13]:





CA

In [14]:

    

st[0:3] // prefix of length 3


    

    
Out[14]:





GCA

In [15]:

    

st[:3] // another way of getting the prefix of length 3


    

    
Out[15]:





GCA

In [16]:

    

st[len(st)-3:len(st)] // suffix of length 3


    

    
Out[16]:





GTC

In [17]:

    

st[-3:] // another way of getting the suffix of length 3


    

    




repl.go:1:5: negative slice index: -3 == Expr{Type: int, Value: -3}

In [18]:

    

st1, st2 := "CAT", "ATAC"


    

In [19]:

    

st1


    

    
Out[19]:





CAT

In [20]:

    

st2


    

    
Out[20]:





ATAC

In [21]:

    

st1 + st2 // concatenation of 2 strings


    

    
Out[21]:





CATATAC