If condition is getting skipped even if the condition is true

Question

I am using an If statement inside a for loop but the If statement is getting skipped even after the condition is met

x=raw_input().split(" ")  
c=[]  
for a in x:  
    b=1  
    if a<0:  
        print "Please enter a number greater than or equal to 0"  
    else:      
        if(a==1 or a==0 ):  
            print "1"  
    for i in range(1,int(a)+1):  
            b=b*i  
    c.append(str(b))  

print ",".join(c)

the program is to find factorial, i am getting the result. If someone enters a negative number, it should not return a factorial but this does. I just want to know why is the if and else conditions getting skipped.

Answer 1

Comparing string with number returns False as result

'-2'< 0 ---> False --> if condition will be skipped

Convert the string to integer since factorial are only applied to integer

int('-2') < 0 ---> True --> if condition will be executed

• x = raw_input().split(" ") returns strings data type in a list

• so you can't use int for the entire list x,

• only one string at the time

When invoking the if condition you are considering only one element in the list,

then convert from string to int before comparing to 0 --> int(a) < 0

---

The second point is related to indentation print (",".join(c)) should be included inside the else loop

Also

if(a==1 or a==0 ):  
                print "1" 

is not needed as it has been taken care in the for loop below

The code is as follow

x=raw_input().split(" ")  
c=[]  
for a in x:  
    b=1  
    if int(a) < 0:  
        print "Please enter a number greater than or equal to 0"  
    else:      
        for i in range(1,int(a)+1):  
            b=b*i  
        c.append(str(b))  
        

        print ",".join(c)