Baby Names

In this chapter you will:

area	topic
🚀	analyze birth statistics
💡	use the open function to read and write files
💡	use the os module to loop through a directory
🔀	parse comma-separated files
🐞	fix FileNotFound errors

The dataset of U.S. baby names

For this chapter, you will need to download a data set of baby names. The authorities of the United States have recorded the first names of all people born as U.S. citizens since 1880. The dataset is publicly available on www.ssa.gov/oact/babynames/limits.html.

Download the shorter archive of baby names (not grouped by states).

Note

For the protection of privacy only names used at least 5 times appear in the data.

Exercise 1: Read a file

Unzip the downloaded archive and place the folder next to your Python program. Read one of the files by inserting line, line, open and print into the gaps.

for ___ in ___(r"names/yob2022.txt"):
    if "Maria" in ___:
       ___(line)

Hint

Depending on your editor, you may need to insert the complete path to the file insted of names/. On Windows, the r is important to have Python correctly interpret backslashes as separators.

Exercise 2: Distinct names

How many different girls names were there in 2022?

Sort the following code lines and indent them correctly:

girls = 0
if "B" in line:
print(girls)
if ",F," in line:
for line in open(r"names/yob2022.txt"):
girls += 1

Exercise 3

Extend the program from the previous exercise such that boys and girls names are counted separately.

Exercise 4: Frequent names

The following program collects names in a list that occur at least 10000 times. Unfortunately, the program contains four errors. Find and fix these.

frequent = []

for line in open(r"names/yob2022.txt"):
    columns = line.strip().split(",")
    name = colums[1]
    if int(columns[3]) >= 10000
        frequent.append(name)

print(frequent)

Exercise 5: Total babies

Write a program that calculates the total number of babies for the year 2022 and writes it to the screen. Compare that number with the year 1922.

Exercise 6: Read and write

Form pairs of Python commands and their meanings.

Exercise 7: Write a file

Execute the following program. Explain what happens.

names = ["Ada", "Bob", "Charlie", "Dorothy"]

with open(r"names.txt", "w") as f:
   for name in names:
       f.write(name + "\n")

Hint

What happens if you remove the \n from the program?

Exercise 8: f-Strings

Try the following commands in a Python shell:

name = "Ada"
number = 42
pi = 3.14159

print(f"{name}")
print(f"{name:>10}")
print(f"{number:5d}")
print(f"{number:05d}")
print(f"{pi:4.1f}")
print(f"{pi:6.3f}")
print(f"name: {name}    number: {number}    pi: {pi:6.3f}")

Exercise 9: Directories

To process bigger amounts of data, you will need to work on more than one file. Sometimes you don’t know all the files in advance. The os module is quite useful for working with many files and directories.

Fill in the gaps:

Exercise 10

Explain the following code:

import os

for dirname in os.listdir(r"names/"):
    print(dirname)

Recap: Read and write text files

Insert working code into the blanks:

# 1. Create a list with the numbers 1..7
...

# 2. Convert the numbers to a string
...

# 3. Open a file for writing
...

# 4. Write the numbers to the file
...

# 5. Open the file for reading
...

# 6. Read all numbers in a list
...

# 7. Sum up the numbers
...

Reflection Questions

• How do you know that a file path in a program is wrong?

• What do you need to check if a file path in a program is wrong?

• How to print all file names in a folder?