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Copy pathfileT.py
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174 lines (103 loc) · 3.41 KB
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# ==========================================
# FILE HANDLING IN PYTHON
# ==========================================
# ---------- OPEN FILE ----------
f = open("data.txt", "r") # read mode
f = open("data.txt", "w") # write mode (overwrite)
f = open("data.txt", "a") # append mode
f = open("data.txt", "x") # create file
f = open("data.txt", "r+") # read + write
f = open("data.txt", "rb") # binary read
f = open("data.txt", "wb") # binary write
# ==========================================
# READ OPERATIONS
# ==========================================
f = open("data.txt", "r")
print(f.read()) # reads entire file
f.seek(0)
print(f.read(5)) # reads first 5 chars
f.seek(0)
print(f.readline()) # reads one line
f.seek(0)
print(f.readlines()) # returns list of lines
f.close()
# ==========================================
# WRITE OPERATIONS
# ==========================================
f = open("data.txt", "w")
f.write("Hello") # writes string
f.writelines(["A\n","B\n"]) # writes multiple lines
f.close()
# ==========================================
# APPEND
# ==========================================
f = open("data.txt", "a")
f.write("\nNew Line")
f.close()
# ==========================================
# WITH STATEMENT (BEST PRACTICE)
# ==========================================
with open("data.txt", "r") as f:
print(f.read())
# automatically closes file
# ==========================================
# FILE POINTER
# ==========================================
f = open("data.txt", "r")
print(f.tell()) # current position
f.read(5)
print(f.tell()) # 5
f.seek(0)
print(f.tell()) # 0
f.close()
# ==========================================
# ITERATE THROUGH FILE
# ==========================================
with open("data.txt","r") as f:
for line in f:
print(line.strip())
# ==========================================
# FILE ATTRIBUTES
# ==========================================
f = open("data.txt","r")
print(f.name) # file name
print(f.mode) # r
print(f.closed) # False
f.close()
print(f.closed) # True
# ==========================================
# CHECK FILE EXISTS
# ==========================================
import os
print(os.path.exists("data.txt"))
# True / False
# ==========================================
# DELETE FILE
# ==========================================
import os
os.remove("data.txt")
# ==========================================
# COMMON MODES
# ==========================================
# r -> read (error if file missing)
# w -> write (creates file, overwrites existing)
# a -> append (creates file if missing)
# x -> create (error if file already exists)
# r+ -> read + write
# rb -> binary read
# wb -> binary write
# ==========================================
# INTERVIEW MCQs
# ==========================================
f = open("data.txt","w")
print(f.write("Hello")) # 5 (chars written)
f.close()
# -----------------------------
with open("data.txt","r") as f:
print(type(f.read())) # <class 'str'>
# -----------------------------
with open("data.txt","r") as f:
print(type(f.readlines())) # <class 'list'>
# -----------------------------
with open("data.txt","r") as f:
print(type(f.readline())) # <class 'str'>