How to generate dynamic function name and call it using user input in Python

user_6331628 0
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I have 10 to 20 function with prefix name same, & I have to call them as per user input, But am not getting how to call them, I tried using below method but it's not working, Can anyone tell me how should I make function callable.

def pattern_1(no):
    print('First Pattern with ' +str(no)+ ' rows')

def pattern_2(no):
    print('Second Pattern with ' +str(no)+ ' rows')


rows = eval(input('Enter number of rows: '))
pattern_no = eval(input('Enter pattern num [1-10]: '))

cust_fun_name = 'pattern_' + str(pattern_no)

print(cust_fun_name) # Here its print pattern_2 but why function is not get invoked
cust_fun_name()

When I run above code am getting below error 

Traceback (most recent call last):                                                                                
  File "/home/main.py", line 22, in <module>                                                                      
    cust_fun_name()                                                                                               
TypeError: 'str' object is not callable
python-3.x function python
3 Answers

if the mapping is static, either make a mapping of function name to function object

mapping = {
  "pattern_1": pattern_1,
  "pattern_2": pattern_2
}

#do not use `eval` on user input!
pattern_no = input('Enter pattern num [1-10]: ')

cust_fun_name = 'pattern_' + str(pattern_no)
cust_func = mapping[cust_fun_name]
# call the function
cust_func()

or get the function object directly from the local namespace

cust_func = locals()['pattern_' + str(pattern_no)]
cust_func()
user_40509250

If you really want to do it this way, you can use eval():

def pattern_1(no):
    print('First Pattern with ' +str(no)+ ' rows')

def pattern_2(no):
    print('Second Pattern with ' +str(no)+ ' rows')

rows = input('Enter number of rows: ')
pattern_no = input('Enter pattern num [1-10]: ')

cust_fun_name = 'pattern_' + pattern_no
print(cust_fun_name) 
eval(cust_fun_name+"("+rows+")") # This is how you use eval()

# Enter number of rows: >? 10
# Enter pattern num [1-10]: >? 1
# pattern_1
# First Pattern with 10 rows

However, I think you should follow Robin's answer, that's the legit way to use Python.

user_67502110 
def pattern_1(no):
    print('First Pattern with ' +str(no)+ ' rows')

def pattern_2(no):
    print('Second Pattern with ' +str(no)+ ' rows')


rows = eval(input('Enter number of rows: '))
pattern_no = eval(input('Enter pattern num [1-10]: '))

pattern_2(no)
cust_fun_name = 'pattern_' + str(pattern_no)

print(cust_fun_name) # Here its print pattern_2 but why function is not get invoked

eval(cust_fun_name)()
user_103684530
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