Why Python-Nmap cannot scan Localhost but Socket can do it?

Question

This is my script and my question is Why Socket scan the Localhost but Nmap can't?

import nmap
import optparse
import socket

tgtHost = "127.0.0.1"
tgtPort = 80

nmScan = nmap.PortScanner()
try:
    result = nmScan.scan(tgtHost, str(tgtPort))
    nmScan.scan(tgtHost, tgtPort)
    state=nmScan[tgtHost]['tcp'][int(tgtPort)]['state']
    print(" [*] " + tgtHost + " tcp/"+tgtPort +" "+state)
except:
    print(f"{tgtHost} is unreachable.")

try:
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.settimeout(0.5)
        s.connect((tgtHost, tgtPort))
        print(f"Port {tgtPort} is open on {tgtHost}.")

except:
    print(f"{tgtHost} is unreachable.") 

This is the result.

Answer 1

Use this method to check if a port is open or closed :

import nmap

tgtHost = "127.0.0.1"
tgtPort = 80

nmScan = nmap.PortScanner()

try:
    result = nmScan.scan(tgtHost, str(tgtPort))
    state = result['scan'][tgtHost]['tcp'][tgtPort]['state']
    print(f"[*] {tgtHost} tcp/{tgtPort} {state}")
except:
    print(f"{tgtHost} is unreachable.")

Output:

[*] 127.0.0.1 tcp/80 closed

Another example: