let's say i have list

strs = ["dog","racecar","car"]

when I = 0 , then I want

d,r,c

when I = 1, then I want

do,ra,ca

when I = 2, then I want

dog,rac,car

like that How can i do this ?

CodePudding user response：

First Part

1.

strs = ["dog","racecar","car"]

l = 0
for a in strs:
    print(a[:l 1],end=' ')

Output

d r c 

---

Explanation.

1. First loop through all the strings in the list.
2. Then print the string only to the l index, I use l 1 because the end is excluded.
3. Means If you run print('hello'[0:3]) it will give all strings to the index 0 to 2 not 3/
4. set end=' ' so it will not ends with a new line.

---

2.

strs = ["dog","racecar","car"]

l = 0
lst = [a[:l 1] for a in strs]
print(*lst) # here *lst is same as print(lst[0],lst[1],...,lst[n]) 

Output

d r c 

---

Second part

1.

strs = ["dog","racecar","car"]

for l in range(min(len(a) for a in strs)):
    for s in strs:
        print(s[:l 1],end=' ')

    print()

Output

d r c 
do ra ca 
dog rac car

2.

strs = ["dog","racecar","car"]


for l in range(min(len(a) for a in strs)):
    print(*[s[:l 1] for s in strs])

Output

d r c 
do ra ca 
dog rac car

---

Explanation for min(len(a) for a in strs)

1. Here inner comprehension(len(a) for a in strs) generates a list with the value as the length of the string inside the list.
2. Then min(len(a) for a in strs) returns the lowest number from the above list.

I hope my explanation is clear. If not please ask me in the comments.

CodePudding user response：

First you need to find the minimum length and then loop through each size up to that length.

strs = ["dog","racecar","car"]

for l in range(min(len(w) for w in strs)):
    print(",".join(s[:l 1] for s in strs))

CodePudding user response：

strs = ["dog","racecar","car"]
def func(arr,n):
    w=""
    for i in range(len(arr)):
        if n<=len(arr[0])-1:
            w =(arr[i])[0:n] " "
        else:
            w =arr[i] " "
    return w;
print(func(strs,2))

Keep on adding sliced portions of each string via loops,If the value of "l" [the variable you used to refer to the final pos] were to exceed the length of the string, the string would be added as a whole. (at least that's how I would handle that case).